Chevrolet - Impala Ss - Workshop Manual - 1995 - 1995

Factory Workshop Manual Make Chevrolet Model Impala Ss Engine and year V8-350 5.7L VIN P MFI (1995) Please navigate through the PDF using the options provided by OnlyManuals.com on the sidebar. This manual was submitted by Anonymous Date 1st January 2018 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Alarm Module, (Vehicle Antitheft) > Component Information > Service and Repair Alarm Module: Service and Repair PROGRAMMING A NEW THEFT DETERRENT MODULE IMPORTANT: Any new PASS-Key II Theft Deterrent Module will automatically program to the resistance of the key (or interrogator setting) being used at the first ignition "ON" cycle. This can only be done once for the life of the module. New modules are unprogrammed. Before the system will function properly after a new module has been installed, it must be programmed to the code that matches the customer1s keys. Programming a new module is very simple: 1. Install the new, unprogrammed module. 2. Insert one of the customer's keys in the ignition lock cylinder and turn it to the "ON" position. It's a good idea to start the Engine at this time to verify system operation. 3. Observe the "PASSKEY" indicator Lamp: ^ The indicator lamp should light for about five seconds and then go out. If the wiring or contacts to the Key Resistance Pellet or the key is defective or intermittent and a new module is installed, the Engine will start but the "PASSKEY" indicator will flash at a rate of one flash per second until the Ignition Switch is turned off. This indicates that the module did not program and that the system components, wiring and contacts should be checked for a fault. IMPORTANT: Before connecting the interrogrator to the ignition lock cylinder circuit, always verify vehicle key code and set the code into the interrogrator using the "key code" knob. This will prevent programming an unprogrammed module with an undesired key code. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Antenna Relay > Component Information > Locations > Power Antenna Relay LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Antenna Relay > Component Information > Locations > Power Antenna Relay > Page 11 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Antitheft Relay > Component Information > Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Antitheft Relay > Component Information > Locations > Page 15 Theft Deterrent Relay Daytime Running Lamps (DRL) Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Emergency Contact Module > Component Information > Technical Service Bulletins > OnStar(R) - Aftermarket Device Interference Information Emergency Contact Module: Technical Service Bulletins OnStar(R) - Aftermarket Device Interference Information INFORMATION Bulletin No.: 08-08-46-004 Date: August 14, 2008 Subject: Information on Aftermarket Device Interference with OnStar(R) Diagnostic Services Models: 2009 and Prior GM Passenger Car and Truck (including Saturn) 2009 and Prior HUMMER H2, H3 Models 2009 and Prior Saab 9-7X with OnStar(R) (RPO UE1) This bulletin is being issued to provide dealer service personnel with information regarding aftermarket devices connected to the Diagnostic Link Connector (DLC) and the impact to OnStar(R) diagnostic probes and Vehicle Diagnostic e-mails. Certain aftermarket devices, when connected to the Diagnostic Link Connector, such as, but not limited to, Scan Tools, Trip Computers, Fuel Economy Analyzers and Insurance Tracking Devices, interfere with OnStar's ability to perform a diagnostic probe when requested (via a blue button call) by a subscriber. These devices also prohibit the ability to gather diagnostic and tire pressure data for a subscriber's scheduled OnStar(R) Vehicle Diagnostic (OVD) e-mail. These aftermarket devices utilize the Vehicles serial data bus to perform data requests and/or information gathering. When these devices are requesting data, OnStar(R) is designed not to interfere with any data request being made by these devices as required by OBD II regulations. The OnStar(R) advisor is unable to definitively detect the presence of these devices and will only be able to inform the caller or requester of the unsuccessful or incomplete probe and may in some cases refer the subscriber/requester to take the vehicle to a dealer for diagnosis of the concern. When performing a diagnostic check for an unsuccessful or incomplete OnStar(R) diagnostic probe, or for concerns regarding completeness of the OnStar(R) Vehicle Diagnostic (OVD) e-mail, verify that an aftermarket device was not present at the time of the requested probe. Regarding the OVD e-mail, if an aftermarket device is interfering (including a Scan Tool of any type), the e-mail will consistently display a "yellow" indication in diagnostics section for all vehicle systems except the OnStar(R) System and Tire Pressure data (not available on all vehicles) will not be displayed (i.e. section is collapsed). Successful diagnostic probes and complete OVD e-mails will resume following the removal or disconnecting of the off-board device. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Relay Module: Customer Interest Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 28 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 29 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 30 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Relay Module: All Technical Service Bulletins Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 36 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 37 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 38 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Memory Positioning Module > Component Information > Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Power Door Lock Relay > Component Information > Locations Power Door Lock Relay: Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Power Door Lock Relay > Component Information > Locations > Page 46 Base Of LH A Pillar With Power Door Locks Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Power Door Lock Relay > Component Information > Locations > Page 47 Power Door Lock Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Power Seat Control Module > Component Information > Locations > Driver Seat Adjuster Memory Module Power Seat Control Module: Locations Driver Seat Adjuster Memory Module Below Center Of Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Power Seat Control Module > Component Information > Locations > Driver Seat Adjuster Memory Module > Page 52 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Seat Heater Control Module > Component Information > Locations > Driver Seat Heater Control Module Seat Heater Control Module: Locations Driver Seat Heater Control Module Attached to seat support, under LH Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Seat Heater Control Module > Component Information > Locations > Driver Seat Heater Control Module > Page 57 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Body and Frame > Trunk / Liftgate Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Brakes and Traction Control > ABS Main Relay > Component Information > Service and Repair ABS Main Relay: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Remove ABS modulator protective cover. 3. Remove relay from modulator. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations Brake Pressure Modulator Valve (With Electronic Brake Control Module) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations > Page 68 Brake Pressure Modulator Valve (BPMV) (With Electronic Brake Control Module (EBCM)) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations > Page 69 Electronic Brake Control Module: Description and Operation DESCRIPTION The EBCM is a small control computer located under the trim panel on the lefthand side of the passenger compartment on wagon models, and on the lefthand side of the luggage compartment on sedan models. This computer monitors the speed of each wheel and the electrical status of the hydraulic modulator. The primary functions of EBCM are to detect wheel locking, control the brake function while in anti-lock mode and monitor system for correct electrical operation. The EBCM also controls the display of the ABS diagnostic trouble codes. If the EBCM detects a fault, it can disable the ABS system and activate the ABS warning lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations > Page 70 Electronic Brake Control Module: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Disconnect EBCM electrical connector. 3. Remove two EBCM to bracket attaching nuts, then the EBCM from the vehicle. 4. Reverse procedure to install, perform ABS system check as described in System Diagnosis. See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems/Testing and Inspection Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Cooling System > Radiator Cooling Fan Motor Relay > Component Information > Locations Radiator Cooling Fan Motor Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Cooling System > Radiator Cooling Fan Motor Relay > Component Information > Locations > Page 75 Engine Cooling Fan Relay Primary, Secondary Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations LH Rear Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations > Page 80 Cruise Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations > Page 81 Cruise Control Module: Description and Operation DESCRIPTION The module has an electronic controller and an electric stepper motor to vary the throttle with each different cruise mode. The module is not serviceable and must be replaced as an assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations > Page 82 Cruise Control Module: Service and Repair Fig. 36 Cruise Control Module Removal 1. Disconnect battery ground cable. 2. Disconnect electrical connector from module, Fig. 36. 3. Disconnect cruise control cable from module, then remove bolts and screws. 4. Remove module and plugs. 5. Remove plugs from module if a new module is being installed. 6. Reverse procedure to install noting the following: a. Align holes in accelerator and cruise control adjuster bracket to holes in wheel house panel and position module on wheel house panel. b. Torque module bolts and screws to 71 ft. lbs. c. Adjust cable, if necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - HVAC > Blower Motor Relay > Component Information > Locations Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - HVAC > Blower Motor Relay > Component Information > Locations > Page 87 LO Blower Relay, Rear Defog Relay And HI Blower Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - HVAC > Compressor Clutch Relay > Component Information > Locations Compressor Clutch Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Courtesy Lamp Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Daytime Running Lamp Control Unit > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Daytime Running Lamp Control Unit > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 99 RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Daytime Running Lamp Control Unit > Component Information > Locations > Page 100 Daytime Running Lamp Control Unit: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Daytime Running Lamp Relay > Component Information > Diagrams Theft Deterrent Relay Daytime Running Lamps (DRL) Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 108 RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 109 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Page 110 Headlamp Control Module: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Page 111 Headlamp Control Module (C2) C406: Body Harness To Tailgate Harness, Headlamp Automatic Control Module (C1), Remote Control Door Lock Receiver Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Lighting and Horns > Horn Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center Convenience Center: Locations Convenience Center LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 120 Behind LH I/P, Left Of Brake Pedal Bracket LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 121 Under I/P Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 122 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Page 123 Convenience Center: Application and ID Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage Engine Control Module: Technical Service Bulletins Engine Controls - Aftermarket Accessory Usage INFORMATION Bulletin No.: 04-06-04-054B Date: November 18, 2010 Subject: Info - Non-GM Parts and Accessories (Aftermarket) Models: 2011 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add model years and update to the new U.S. Fixed Operation Manager (FOM) and Canada Warranty Manager (WM) names. Please discard Corporate Bulletin Number 04-06-04-054A (Section 06 - Engine/Propulsion System). The recent rise and expansion of companies selling non-GM parts and accessories has made it necessary to issue this reminder to dealers regarding GM's policy on the use and installation of these aftermarket components. When a dealer is performing a repair under the New Vehicle Limited Warranty, they are required to use only genuine GM or GM-approved parts and accessories. This applies to all warranty repairs, special policy repairs or any repairs paid for by GM. Parts and accessories advertised as being "the same" as parts manufactured by GM, but not sold through GM, do not qualify for use in warranty repairs, special policy repairs or any repairs paid for by GM. During a warranty repair, if a GM original equipment part is not available through GM Customer Care and Aftersales (GM CC&A;), ACDelco(R) distributors, other GM dealers or approved sources, the dealer is to obtain comparable, non-GM parts and clearly indicate, in detail, on the repair order the circumstances surrounding why non-GM parts were used. The dealer must give customers written notice, prior to the sale or service, that such parts or accessories are not marketed or warranted by General Motors. It should also be noted that dealers modifying new vehicles and installing equipment, parts and accessories obtained from sources not authorized by GM are responsible for complying with the National Traffic and Motor Vehicle Safety Act. Certain non-approved parts or assemblies, installed by the dealer or its agent not authorized by GM, may result in a change to the vehicle's design characteristics and may affect the vehicle's ability to conform to federal law. Dealers must fully understand that non-GM approved parts may not have been validated, tested or certified for use. This puts the dealer at risk for potential liability in the event of a part or vehicle failure. If a GM part failure occurs as the result of the installation or use of a non-GM approved part, the warranty will not be honored. A good example of non-authorized modification of vehicles is the result of an ever increasing supply of aftermarket devices available to the customer, which claim to increase the horsepower and torque of the Duramax(TM) Diesel Engines. These include the addition of, but are not limited to one or more of the following modifications: - Propane injection - Nitrous oxide injection - Additional modules (black boxes) that connect to the vehicle wiring systems - Revised engine calibrations downloaded for the engine control module - Calibration modules which connect to the vehicle diagnostic connector - Modification to the engine turbocharger waste gate Although the installation of these devices, or modification of vehicle components, can increase engine horsepower and torque, they may also negatively affect the engine emissions, reliability and/or durability. In addition, other powertrain components, such as transmissions, universal joints, drive shafts, and front/rear axle components, can be stressed beyond design safety limits by the installation of these devices. General Motors does not support or endorse the use of devices or modifications that, when installed, increase the engine horsepower and torque. It is because of these unknown stresses, and the potential to alter reliability, durability and emissions performance, that GM has adopted a policy that prevents any UNAUTHORIZED dealer warranty claim submissions to any remaining warranty coverage, to the powertrain and driveline components whenever the presence of a non-GM (aftermarket) calibration is confirmed - even if the non-GM control module calibration is subsequently removed. Refer to the latest version of Bulletin 09-06-04-026 (V8 Gas Engines) or 06-06-01-007 (Duramax(TM) Diesel Engines) for more information on dealer requirements for calibration verification. These same policies apply as they relate to the use of non-GM accessories. Damage or failure from the use or installation of a non-GM accessory will not be covered under warranty. Failure resulting from the alteration or modification of the vehicle, including the cutting, welding or disconnecting of the vehicle's original equipment parts and components will void the warranty. Additionally, dealers will NOT be reimbursed or compensated by GM in the event of any legal inquiry at either the local, state or federal level that Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 130 results from the alteration or modification of a vehicle using non-GM approved parts or accessories. Dealers should be especially cautious of accessory companies that claim the installation of their product will not void the factory warranty. Many times these companies have even given direction on how to quickly disassemble the accessory in an attempt to preclude the manufacturer from finding out that is has been installed. Any suspect repairs should be reviewed by the Fixed Operations Manager (FOM), and in Canada by the Warranty Manager (WM) for appropriate repair direction. If it is decided that a goodwill repair is to be made on the vehicle, even with the installation of such non-GM approved components, the customer is to be made aware of General Motors position on this issue and is to sign the appropriate goodwill documentation required by General Motors. It is imperative for dealers to understand that by installing such devices, they are jeopardizing not only the warranty coverage, but also the performance and reliability of the customer's vehicle. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 131 Engine Control Module: Technical Service Bulletins PROM - Reprogram Using Off Board Program Adapter File In Section: 6E - Engine Fuel & Emission Bulletin No.: 73-65-13 Date: March, 1997 INFORMATION Subject: Reprogramming Capability using the Off Board Programming Adapter Models: 1993-97 Passenger Cars and Trucks (Applicable Reprogrammable Vehicles) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 132 The General Motors vehicles contain Electronically Reprogrammable Devices (i.e. PCM, VCM, ECM). These vehicles cannot be programmed through PROM replacement, however service programming capability is available through the Tech 1/1A, Tech 2 and Techline terminals via direct or remote programming. The Environmental Protection Agency (EPA) has requested that all new vehicle manufacturers ensure their dealers/retailers are aware that they are responsible for providing customers access to reprogramming services at a reasonable cost and in a timely manner. Although programming of controllers has become a common service practice at GM dealers/retailers, the EPA has received reports from consumers and the aftermarket repair industry that they were unable to purchase a new (programmed) Electronically Reprogrammable Device (ERD) over-the-counter. As a result, on August 1, 1995, the Federal Government issued a regulation requiring all manufacturers to make available reprogramming to the independent aftermarket by December 1, 1997. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 133 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 134 Today, the Off Board Programming Adapter (OBPA) is used to reprogram ERD's sold over-the-counter. For all practical purposes, the OBPA takes the place of the vehicle when the vehicle is not available. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 135 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 136 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 137 The list of dealerships/retailers currently own the OBPA (see Attachments 1 - 3). These locations are equipped to provide over-the-counter preprogrammed ERD's. The hardware required to perform reprogramming in addition to the OBPA is a Techline terminal, Tech 1/1A and associated cables and adapters. THE TECH 2 SHOULD NOT BE USED WITH THE OBPA AT THIS TIME BECAUSE OF INADEQUATE OBPA GROUNDING. The current OBPA can support reprogramming on all late model General Motor's vehicles except: ^ Premium V-8's ^ 1996 Diesel Truck ^ Cadillac Catera Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 138 ^ All 1997 programmable vehicles (requires use of the Tech 2) A modification to the OBPA is being offered by Kent-Moore to support these additional vehicles and to allow reprogramming using the Tech 2. The revisions to the OBPA for the Tech 2 is very important as the Tech 2 is the only tool used for service programming for 1997 and future vehicles. To have the modifications performed, contact Kent-Moore at (800) 345-2233. The revisions (part number J 41207 REV-C) are free of charge for GM dealerships/retailers. A dealership/retailer can purchase the OBPA by contacting Kent-Moore (part number J 41207-C). Support on how to use the OBPA is provided by the Techline Customer Support Center (TCSC) at (800) 828-6860 (English) or (800) 503-3222 (French). If you need to purchase an OBPA and/or cable, contact Kent-Moore at (800) 345-2233. The OBPA retails for $695.00 (includes all revisions 1-4) under part number J 41207-C. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Page 139 Engine Control Module: Specifications Powertrain Control Module (PCM) .............................................................................................................................................................. 3 Nm (26 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations PCM Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 142 Engine Control Module: Connector Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 143 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 144 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 145 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions Engine Control Module: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 148 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 149 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 150 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 151 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 152 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 153 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 154 Engine Control Module: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 155 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 156 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 157 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 158 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 159 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 160 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 161 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 162 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 163 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 164 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 165 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 166 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 167 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 168 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 169 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 170 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 171 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 172 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 173 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 174 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 175 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 176 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 177 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 178 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 179 Engine Control Module: Connector Views Powertrain Control Module (PCM): A Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 180 Powertrain Control Module (PCM): B Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 181 Powertrain Control Module (PCM): C Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 182 Powertrain Control Module (PCM): D Pinout Information PCM Connectors CAUTION: Do not backprobe Powertrain Control Module (PCM) connectors! The connectors are sealed for operation in an underhood environment. Backprobing may damage the seal which could eventually cause the connector to fail due to corrosion. This information applies to the PCM connector charts in the next four images. These charts may be used with the J 39700-A breakout box in conjunction with J 39700-110 and J 39700-140 cables and high impedance digital multimeter J 39200 to obtain voltage present for each circuit listed. Install the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 183 breakout box between the PCM connectors and the PCM. The breakout box PIN numbers correspond with the PCM connector PIN numbers. Voltage may vary slightly, but should be very close. Certain exceptions are called out in the chart legend below. The following conditions must be met before checking typical voltages: Key "ON": ^ DVM negative (black) lead connected to a known good ground. ^ Scan tool "NOT" installed. ^ All accessories "OFF." ^ Battery fully charged. Engine Running: ^ All conditions listed above. ^ Engine at normal operating temperature. ^ Engine at idle/closed throttle/operating in "Closed Loop." ^ In park or neutral. CHART LEGEND (1) Less than .5 volt when system enabled. (2) Battery voltage for first two seconds with ignition "ON." (3) Varies. (4) Varies with temperature. (5) Battery voltage when in gear. (6) Less than .5 volt with brake pedal applied. (7) Battery voltage with A/C "ON." (8) Varies with altitude. (9) Less than .5 volt with high power steering load. (*) Less than .5 volt. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 184 Connector "A" RED Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 185 Connector "B" BLACK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 186 Connector "C" GREY/CLEAR Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 187 Connector "D" BLUE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Page 188 Engine Control Module: Description and Operation PCM Connectors The Powertrain Control Module (PCM) is the control center of the fuel injection system. It constantly looks at the information from various sensors and controls the systems that affect vehicle performance. The PCM also performs a diagnostic function check of the system. It can recognize operational problems and alert the driver through the Malfunction Indicator Lamp (MIL) "Service Engine Soon" and store Diagnostic Trouble Code(s) (DTC) which identify the problem areas to aid the technicians making repairs. The PCM supplies 5 or 12 volts to power various sensors or switches. This is done through resistances in the PCM which are so high in value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading because its resistance is too low. Therefore, the use of a 10 megohm input impedance digital voltmeter (J 39200) is required to assure accurate voltage readings. Refer to Computers and Controls / System Diagnosis / Flow of Diagnosis / "Strategy Based Diagnostics" for more information on using the diagnostic function of the PCM. MEMORY There are three types of memory storage within the PCM: Read Only Memory (ROM), Random Access Memory (RAM) and Electrically Erasable Programmable Read Only Memory (EEPROM). ROM Read Only Memory (ROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The ROM contains the overall control programs. Once the ROM is programmed, it cannot be changed. The ROM memory is non-erasable, and does not need power to be retained. RAM Random Access Memory (RAM) is the microprocessor "scratch pad." The processor can write into, or read from this memory as needed. This memory is erasable and needs a constant supply of voltage to be retained. If the voltage is lost, the memory is lost. EEPROM Electrically Erasable Programmable Read Only Memory (EEPROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The EEPROM contains the overall control algorithms. The EEPROM can be reprogrammed by using the Tech 1 scan tool or other Decline terminal/equipment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Component Tests and General Diagnostics Engine Control Module: Component Tests and General Diagnostics To display diagnostic trouble codes, use a Tech 1 (or equivalent scanner). Grounding the DLC will NOT flash Diagnostic Trouble Code(s) (DTC), but will enable most outputs when the ignition is "ON" engine "OFF." Grounding the Data Link Connector (DLC) while the engine is running will cause the Malfunction Indicator Lamp (MIL) to flash to indicate "Open" or "Closed Loop. This is referred to as Field Service Mode." To clear the DTCs from memory use the Tech 1 or: ^ ignition "OFF." ^ Disconnect the # 2 fuse (located in the underhood electrical center) for 30 seconds. Since the Powertrain Control Module (PCM) can have a failure which may affect only one circuit, following the diagnostic procedures in this section will determine which circuit has a problem and where it is. If a diagnostic chart indicates that the PCM connections or PCM is the cause of a problem and the PCM is replaced the Knock Sensor (KS) module must be transferred to the new PCM and the new PCM must then be programmed. If this does not correct the problem, one of the following may be the reason: ^ There is a problem with the PCM terminal connections. The diagnostic chart will say PCM connections or PCM. The terminals may have to be removed from the connector in order to check them properly. ^ The problem is intermittent. This means that the problem is not present at the time the system is being checked. In this case. Refer to Diagnosis by Symptom and make a careful physical inspection of all portions of the system involved. ^ Shorted solenoid, relay coil, or harness. Solenoids and relays are turned "ON" and "OFF" by the PCM using internal electronic switches called "drivers." A shorted solenoid, relay coil, or PCM harness will not damage the PCM but will cause the component to be inoperative. J 34636 or BT-8405 testers or equivalent provide a fast accurate means of checking for a shorted coil or a short to battery voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 191 Engine Control Module: Service and Repair Removal Hardware Removal NOTE: To prevent internal Powertrain Control Module (PCM) damage, the ignition must be "OFF", when disconnecting or reconnecting power to the PCM. Remove or Disconnect: 1. Disconnect negative battery cable 2. Disconnect PCM mounting hardware 3. Disconnect PCM electrical connectors 4. Remove PCM from engine compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 192 PCM With Knock Sensor Module 5. Remove PCM access cover Removing Knock Sensor Module From PCM 6. Remove knock sensor module from PCM Install or Connect: 1. Install knock sensor module and access cover 2. Install PCM in vehicle 3. Connect PCM electrical connectors 4. Connect PCM mounting hardware 5. Connect negative battery cable EEPROM Programming CAUTION:The software/calibration used for PCM reprogramming must match the vehicle application, or improper operation and/or damage may occur. ^ Ensure battery is charged ^ Turn ignition "ON" ^ Ensure connections to the Data Link Connector (DLC) and battery/cigar lighter are secure ^ Follow the most current Decline terminal/equipment instructions Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 193 PCM Reprogramming Failure ^ Check PCM connections ^ Check Decline terminal/equipment for latest software version ^ Repeat reprogramming procedures. If it fails again, replace the PCM. The replacement PCM must be programmed. PCM Functional Check ^ Refer to System Diagnosis / Diagnostic System Check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Knock Sensor Module > Component Information > Locations PCM With Knock Sensor Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Knock Sensor Module > Component Information > Locations > Page 197 Knock Sensor Module: Service and Repair PCM With Knock Sensor Module Removing Knock Sensor Module From PCM REMOVE OR DISCONNECT 1. Negative battery cable. 2. Powertrain Control Module (PCM) from mounting bracket (refer to PCM removal). 3. Knock sensor (KS) module access cover. 4. Knock sensor module. INSTALL OR CONNECT NOTICE: To prevent possible electrostatic discharge damage to the PCM and KS module, Do Not touch the connector pins or soldered components on the circuit board. 1. Knock senor module. 2. Access cover. 3. PCM to mounting bracket (refer to PCM installation). 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Emission Control Systems > Air Injection Pump Relay > Component Information > Locations Air Injection Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Emission Control Systems > Air Injection Pump Relay > Component Information > Locations > Page 202 Air Injection Pump Relay: Description and Operation Chart C-6 The Powertrain Control Module (PCM) controls operation of the electric air pump relay which in turn controls air availability to the air injection system. The PCM completes the ground to the coil side of the relay. The relay in turn activates the electric air pump and the integral stop valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Locations Fuel Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions Fuel Pump Relay: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 209 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 210 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 211 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 212 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 213 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 214 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 215 Fuel Pump Relay: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 216 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 217 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 218 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 219 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 220 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 221 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 222 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 223 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 224 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 225 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 226 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 227 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 228 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 229 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 230 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 231 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 232 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 233 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 234 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 235 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 236 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 237 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 238 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 239 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Page 240 Fuel Pump Relay: Description and Operation When the ignition switch is turned to the "ON" position (before engaging starter), the energizes the fuel pump relay for two seconds causing the fuel pump to pressurize the fuel system. If the Powertrain Control Module (PCM) does not receive ignition reference pulses (engine cranking or running) within two seconds, it shuts "OFF" the fuel pump relay, causing the fuel pump to stop. As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Page 241 Fuel Pump Relay: Service and Repair Fuel Pump (Circuit Opening) Relay REMOVE OR DISCONNECT 1. Underhood (U/H) electrical center cover. 2. Fuel pump relay. INSTALL OR CONNECT 1. Fuel pump relay. 2. Underhood (U/H) electrical center cover. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Specifications Ignition Control Module: Specifications Ignition Coil Assembly Bolt / Screw ........................................................................................................................................................... 25 Nm (18 lb ft.) Ignition Coil Assembly Stud ................................................................................................................. ...................................................... 25 Nm (18 lb ft.) Ignition Coil Module Bolt / Screw ............................................................................................................................................................. 1.7 Nm (15 lb in.) Replacement Coil to-Bracket Bolt / Screw ................................................................................................................................................. 2.8 Nm (25 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector Engine Left Side Upper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector > Page 248 Ignition Control Module: Locations Ignition Module Ignition Coil Ignition Coil And Ignition Control Module The Ignition Control Module is located on the ignition coil bracket assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 249 Ignition Control Module: Description and Operation Ignition Coil And Module Assembly Ignition Coil And Module The ignition coil/ignition control module assembly provides spark to the distributor assembly, timed by signals from the ECM. Power (B+) for the ignition coil primary circuit and the ignition control module is supplied by the ignition switch. The ECM combines the camshaft position information supplied by the distributor with other system parameters and calculates the required spark advance and coil dwell. The ECM signals the ignition control module, which turns on the primary current to the ignition coil by grounding the primary circuit, and then turns it off by removing the ground. When the primary current flow stops, high voltage induced in the ignition coil secondary winding becomes the spark voltage for the spark plug. The spark voltage is delivered to the distributor assembly through the coil output (secondary) wire, and then directed to the proper spark plug connector by the distributor rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 250 Ignition Control Module: Service and Repair Ignition Coil Ignition Coil And Ignition Control Module Numbers used below refer to image caption. REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Four-terminal Powertrain Control Module (PCM) connector at ignition coil module. 3. Ignition coil wiring connectors. 4. Ignition coil harness. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 251 5. Studs (5). 6. Ignition coil / Ignition Control Module assembly (8). ^ Do not wipe silicone grease from bottom of ignition coil assembly (8) if it is to he reinstalled. DISASSEMBLE 1. Coil (10) from brackets (13 and 14) by drilling out rivets (9). 2. Bolts/screws (12). 3. Ignition control module (11). NOTICE: If a new ignition coil assembly is to be installed, a package of silicone grease will be included in the box. This grease is necessary for ignition coil assembly cooling. ASSEMBLE 1. Spread silicone grease on metal face of ignition control module (11) and on bracket (13) where it seats, and position ignition control module (11) to bracket (13). 2. Bolts / screws (12). Tighten ^ Bolts / screws (12) to 1.7 Nm (15 lb in.). 3. Coil (10) to brackets (13 and 14) using bolts / screws provided with replacement coil (10). Tighten ^ Bolts / screws to 2.8 Nm (25 lb in.). INSTALL OR CONNECT 1. Spread silicone grease on metal mounting face of ignition coil bracket (14) if necessary, and position ignition coil / Ignition Control module assembly (8) to cylinder head assembly. 2. Studs (5). Tighten ^ Studs (5) to 25 Nm (18 lb ft.). 3. Ignition coil harness. 4. Ignition coil wiring connectors. 5. Four terminal PCM connector to ignition coil module. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > System Component Locations Description Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > System Component Locations > Page 257 LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > Page 258 Inflatable Restraint Diagnostic Energy Reserve (With Sensor) Module (SDM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > Page 259 Air Bag Control Module: Description and Operation DESCRIPTION The Sensing and Diagnostic Module (SDM) performs several system functions. These functions include energy reserve, air bag deployment, malfunction detection, malfunction diagnosis, driver notification, frontal crash detection and frontal crash recording. OPERATION The SDM contains a sensing device which converts vehicle velocity changes to an electrical signal. The electrical signal generated is processed by the SDM and then compared to a value stored in memory. When the generated signal exceeds the stored value, additional signals are compared to signals stored in memory. When two of the generated signals exceed the stored values or when one of the generated signals exceeds the stored value and the forward discriminating sensor closes, the SDM will cause current to flow through the inflator modules deploying the air bags. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Steering and Suspension > Relays and Modules - Steering > Steering Control Module > Component Information > Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Steering and Suspension > Relays and Modules - Steering > Steering Control Module > Component Information > Locations > Page 265 Power Steering Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Steering and Suspension > Relays and Modules - Suspension > Compressor/Pump Relay, Suspension Control > Component Information > Description and Operation Compressor/Pump Relay: Description and Operation DESCRIPTION The compressor relay is controlled by the height sensor and completes the 12-volt circuit to the compressor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Windows and Glass > Heated Glass Element Relay > Component Information > Locations Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Relays and Modules > Relays and Modules - Windows and Glass > Heated Glass Element Relay > Component Information > Locations > Page 274 LO Blower Relay, Rear Defog Relay And HI Blower Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Component Locations Power Door Lock Switch: Component Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Component Locations > Page 281 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Component Locations > Page 282 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Page 283 Power Door Lock Switch RH And LH Front Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Mirror Switch > Component Information > Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Locations > Component Locations Power Seat Switch: Component Locations Driver Seat Switch Pod Bottom Of driver Seat, outboard Side Passenger Seat Switch Pod Part of bottom Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Locations > Component Locations > Page 291 Power Seat Switch: Connector Locations RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Locations > Component Locations > Page 292 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Diagrams > LH and RH Lumbar Switch Assembly C312 & C313: LH And RH Lumbar Switch Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Diagrams > LH and RH Lumbar Switch Assembly > Page 295 Power Seat Switch LH And RH Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Seat Heater Switch > Component Information > Locations > Driver Seat Heater Switch Seat Heater Switch: Locations Driver Seat Heater Switch LH side of Driver's Seat Cushion Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Seat Heater Switch > Component Information > Locations > Driver Seat Heater Switch > Page 300 Seat Heater Switch: Locations Passenger Seat Heater Switch LH side of Passenger Seat Cushion Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Seat Memory Switch > Component Information > Locations Seat Memory Switch: Locations LH Front door on armrest Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Component Locations Trunk / Liftgate Switch: Component Locations Trunk Lid With Pull-Down Back View Of LH Instrument Panel Rear Compartment Lid Enable Switch Mounted on I/P Compartment Rear Luggage Compartment With Pull-Down Rear Compartment Lid Pull-Down Striker Switch Attached to Rear Compartment Lid Pulldown Actuator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Component Locations > Page 308 Rear Compartment Lid Pull-Down Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Component Locations > Page 309 Trunk Lid With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Page 310 Rear Glass Interlock/Push Button Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Brake Fluid Level Sensor/Switch > Component Information > Description and Operation Brake Fluid Level Sensor/Switch: Description and Operation OPERATION This sensor mounted on the master cylinder will activate the Brake Warning lamp if a low brake fluid level is detected. The lamp will turn off once the fluid level is corrected. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Brake Fluid Pressure Sensor/Switch > Component Information > Locations LH Rear Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Brake Fluid Pressure Sensor/Switch > Component Information > Locations > Page 318 Brake Fluid Pressure Sensor/Switch: Description and Operation Fig. 3 Pressure Differential Valve & Brake Warning Lamp Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Brake Fluid Pressure Sensor/Switch > Component Information > Locations > Page 319 Fig. 4 Dual Master Cylinder W/Built In Warning Lamp Switch. DESCRIPTION In Fig. 3, as pressure falls in one system, the other system's normal pressure forces the piston to the inoperative side, contacting the switch terminal, causing the warning lamp on the instrument panel to glow. In Fig. 4 shows the switch mounted directly in the master cylinder assembly. Whenever there is a specified differential pressure, the switch piston will activate the brake failure warning switch and cause the brake warning lamp to glow. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch > Page 324 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front Wheel Speed Sensor: Locations Wheel Speed Sensor Lead, Front LH Rear Engine Compartment LH Front Frame Rail RH Front Frame Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 329 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 330 Wheel Speed Sensor: Locations Wheel Speed Sensor, Rear LH Rear Frame Rail (Without Automatic Level Control) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 331 Antilock Brake System Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Page 332 Wheel Speed Sensor: Description and Operation DESCRIPTION These sensors transmit wheel speed information to the EBCM using a small amount of AC voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor Wheel Speed Sensor: Service and Repair Left Front Wheel Speed Sensor REPLACEMENT 1. Raise and support vehicle. 2. Disconnect wheel speed sensor harness connector and sensor assembly connector from clip. 3. Disconnect speed sensor connector from harness connector. 4. Remove sensor bracket attaching bolt from frame rail. 5. Disconnect wheel speed sensor assembly harness with grommets from brackets and combination valve brake pipe clip. Note position of grommets and harness for installation reference. 6. Remove speed sensor retaining bolt, then the speed sensor from steering knuckle. 7. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the knuckle and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor > Page 335 Wheel Speed Sensor: Service and Repair Rear Axle Speed Sensor 1. Raise and support vehicle. 2. Unclip sensor assembly connector and differential sensor connector, then separate the connectors. 3. Disconnect speed sensor harness assembly wiring harness with gromments from sensor bracket. Note position of grommets and harness for installation reference. 4. Remove sensor attaching bolt, then the sensor from the vehicle. 5. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the axle housing and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor > Page 336 Wheel Speed Sensor: Service and Repair Right Front Wheel Speed Sensor REPLACEMENT 1. Disconnect forward lamp harness wheel speed sensor connector and wheel speed sensor assembly connector from clip. 2. Disconnect forward lamp harness connector from wheel speed sensor connector. 3. Raise and support vehicle. 4. Remove sensor bracket attaching bolt from frame rail. 5. Remove sensor assembly harness with grommets from brackets. Note position of grommets and harness for assembly reference. 6. Remove sensor retaining bolt, then the sensor from vehicle. 7. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the knuckle and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cooling System > Coolant Level Sensor > Component Information > Locations Rear Side Radiator Support, Coolant Fans Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications Coolant Temperature Sensor/Switch (For Computer): Specifications Engine Coolant Temperature (ECT) Sensor ................................................................................................................................................ 23 Nm (17 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 345 Coolant Temperature Sensor/Switch (For Computer): Locations Left Front Of Engine The engine coolant temperature sensor is located near water pump. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 346 Coolant Temperature Sensor/Switch (For Computer): Description and Operation Engine Coolant Temperature Sensor The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) immersed in the engine coolant stream. Low coolant temperature produces a high resistance while high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the ECT through a resistor in the PCM and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage. the PCM knows the engine coolant temperature. Engine coolant temperature affects most systems the PCM controls. A failure in the ECT circuit should set either a Diagnostic Trouble Code (DTC) 14 or 15. Remember these DTCs indicate a failure in the engine coolant temperature sensor circuit, so proper use of the chart will lead to either repairing a wiring problem or replacing the sensor to properly repair a problem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 347 Coolant Temperature Sensor/Switch (For Computer): Service and Repair Engine Coolant Temperature Sensor IMPORTANT: Care must be taken when handling engine coolant (ECT) temperature sensor. Damage to engine coolant sensor will affect proper operation of the fuel injection system. REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Relieve coolant pressure. 3. Electrical connector. 4. Carefully back out sensor. INSTALL OR CONNECT 1. Coat threads with sealer. 2. Install sensor in engine. 3. Torque to 23 Nm (17 ft lb). 4. Connect electrical connector. 5. Refill lost coolant. 6. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Radiator Cooling Fan Temperature Sensor / Switch > Component Information > Locations Radiator Cooling Fan Temperature Sensor / Switch: Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Temperature Sensor (Gauge) > Component Information > Locations Temperature Sensor (Gauge): Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Brake Switch (Cruise Control) > Component Information > Service and Repair Brake Switch (Cruise Control): Service and Repair Fig. 3 Cruise Control Release Switch & Stop Lamp Switch Assemblies 1. Disconnect electrical connectors, then remove release switch and stop lamp switch assemblies from retainers, Fig. 3. 2. Remove retainers from bracket. 3. Reverse procedure to install. Adjust as outlined. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations > Page 362 Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations > Page 363 Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Page 364 C215: Cruise Control Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Page 365 Cruise Control Switch: Description and Operation Fig. 3 Cruise Control Release Switch & Stop Lamp Switch Assemblies DESCRIPTION The release switch and stop lamp switch cannot be adjusted until after the brake booster pushrod is assembled to brake pedal assembly. Refer to Fig. 3 when performing this procedure. OPERATION 1. Depress brake pedal and insert release switch and stop lamp switch assembly into retainers until fully seated. 2. Slowly release brake pedal back to its original position. Release switch and stop lamp switch assemblies will move within retainers to their adjusted position. 3. The following brake pedal travel distances can be used to check for properly adjusted release switch and stop lamp switch assemblies: a. Release switch and stop lamp switch assemblies contacts must be open at 1/8-1/2 inch brake pedal travel, measured at centerline of brake pedal pad. b. Nominal actuation of stop lamp switch contacts is about 3/16 inch after cruise switch control contacts close. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Page 366 Cruise Control Switch: Service and Repair The engagement switch is not serviceable. The complete turn signal, headlamp dimmer switch, cruise control actuator and windshield wiper/washer must be replaced as an assembly. 1. Disconnect battery ground cable. 2. Remove steering column access cover, then disconnect electrical connector. Ensure windshield wiper switch is in Off position. 3. Remove lever assembly by pulling straight out. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Cruise Control > Vehicle Speed Sensor/Transducer - Cruise Control > Component Information > Description and Operation Vehicle Speed Sensor/Transducer - Cruise Control: Description and Operation DESCRIPTION The Vehicle Speed Sensor (VSS) buffer receives a signal from the VSS (permanent magnet generator) indicating vehicle speed. The buffer processes the signal which is then sent to the Engine Control Module (ECM), cruise control module and speedometer. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Locations Engine, Left Side Lower Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions Oil Level Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 376 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 377 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 378 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 379 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 380 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 381 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 382 Oil Level Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 383 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 384 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 385 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 386 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 387 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 388 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 389 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 390 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 391 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 392 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 393 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 394 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 395 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 396 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 397 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 398 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 399 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 400 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 401 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 402 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 403 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 404 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 405 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 406 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Sender > Component Information > Locations Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Specifications Oil Pressure Switch (For Fuel Pump): Specifications Fuel Pump Switch and Engine Oil Pressure Sensor ................................................................................................................................... 12 Nm (106 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch > Page 415 Oil Pressure Switch (For Fuel Pump): Locations Oil Pressure Sensor/Fuel Pump Switch Fuel Pump - Oil Pressure Switch The sensor is threaded into a TEE fitting at the rear of the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions Oil Pressure Switch (For Fuel Pump): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 418 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 419 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 420 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 421 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 422 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 423 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 424 Oil Pressure Switch (For Fuel Pump): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 425 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 426 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 427 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 428 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 429 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 430 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 431 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 432 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 433 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 434 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 435 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 436 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 437 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 438 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 439 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 440 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 441 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 442 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 443 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 444 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 445 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 446 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 447 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 448 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 449 Fuel Pump Switch/Engine Oil Pressure Gage Sensor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 450 Fuel Pump Relay Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 451 Oil Pressure Switch (For Fuel Pump): Description and Operation Fuel Pump - Oil Pressure Switch As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 452 Oil Pressure Switch (For Fuel Pump): Service and Repair Fuel Pump - Oil Pressure Switch REMOVE OR DISCONNECT 1. Disconnect electrical connector. 2. Fuel pump switch and oil pressure sensor. INSTALL OR CONNECT 1. Fuel pump switch and oil pressure sensor. 2. Tighten to 12 Nm (106 lb in.) 3. Electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Air Conditioning Switch > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Ambient Temperature Sensor / Switch HVAC > Component Information > Locations > Inside Air Temperature Sensor Ambient Temperature Sensor / Switch HVAC: Locations Inside Air Temperature Sensor Instrument Panel Carrier, above Glove Box. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Ambient Temperature Sensor / Switch HVAC > Component Information > Locations > Inside Air Temperature Sensor > Page 461 Ambient Temperature Sensor / Switch HVAC: Locations Outside Air Temperature Sensor Attached to Hood Latch Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Blower Motor Switch > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Blower Motor Switch > Component Information > Locations > Page 465 Heater And A/C Blower Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Refrigerant Pressure Sensor / Switch, HVAC > Component Information > Locations > A/C Compressor Pressure Cycling Switch Refrigerant Pressure Sensor / Switch: Locations A/C Compressor Pressure Cycling Switch Engine Harness/U/Hood Electrical Center, Right Side Attached to A/C accumulator, RH rear of Engine Compartment RH Rear Engine Compartment attached to A/C Accumulator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Refrigerant Pressure Sensor / Switch, HVAC > Component Information > Locations > A/C Compressor Pressure Cycling Switch > Page 470 Refrigerant Pressure Sensor / Switch: Locations A/C Refig Press Sensor Component Location - Pictorial View In High Pressure Line, below Coolant Reservoir Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - HVAC > Solar Sensor, HVAC > Component Information > Locations Solar Sensor: Locations Near center of I/P Upper Trim Pad (in Defroster Grille) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Technical Service Bulletins > IP Dimmer Control - Proper Setting Dimmer Switch: Technical Service Bulletins IP Dimmer Control - Proper Setting File In Section: 08 - Body and Accessories Bulletin No.: 99-08-42-009 Date: November, 1999 INFORMATION Subject: Proper Setting of I/P Dimmer Control to View PRNDL Display with Automatic Headlamp Control Models: 2000 and Prior All Passenger Cars and Trucks With Automatic Headlamp Control and Electronic PRNDL Display Under certain conditions, if the instrument panel dimmer control is turned relatively low, the PRNDL will not be visible until the automatic headlamp control turns the headlamps off and the daytime running lamps (DRL) are turned back on. Such a condition may be if the vehicle is first started in an environment where the headlamp control turns on the headlamps and then the vehicle is driven out into a brighter environment (for example, when a vehicle is backed out of a dark garage into the bright sunlight). This condition is normal and any repair attempt will not be successful. Demonstrate this condition to the customer using the service lane and then turn the instrument panel dimmer control to a higher setting. This will enable the driver to see the PRNDL display Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Component Locations Dimmer Switch: Component Locations Lower LH Side Of Steering Column Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Component Locations > Page 481 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Page 482 Dimmer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Page 483 Dimmer Switch: Service and Repair Fig. 13 Column Mounted Dimmer Switch Installation 1. Disconnect battery ground cable. 2. Remove instrument panel lower trim and on models with A/C, remove A/C duct extension at column. 3. Disconnect shift indicator from column and remove toe-plate cover screws. 4. Remove two nuts from instrument panel support bracket studs and lower steering column, resting steering wheel on front seat. 5. Remove dimmer switch retaining screws, then the switch. Tape actuator rod to column and separate switch from rod. 6. Reverse procedure to install. To adjust switch, depress dimmer switch slightly and install a 3/32 inch twist drill to lock switch to the body, Fig. 13. Force switch upward to remove lash between switch and pivot, then remove tape from actuator rod. Remove twist drill and check for proper operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 488 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 489 Door Switch: Locations Door Jamb Switch, RH Front Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 490 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 491 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Fuel Gauge Sender > Component Information > Locations Fuel Gauge Sender: Locations Mounted on Fuel Tank, Part of Fuel Tank Unit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Fuel Gauge Sender > Component Information > Locations > Page 495 Fuel Pump/Sender Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Instrument Panel > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch > Page 500 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Ambient Light Sensor > Component Information > Locations Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Backup Lamp Switch > Component Information > Locations Backup Lamp Switch: Locations RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Backup Lamp Switch > Component Information > Locations > Page 508 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Brake Light Switch > Component Information > Locations Brake Light Switch: Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Brake Light Switch > Component Information > Locations > Page 512 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Brake Light Switch > Component Information > Locations > Page 513 Brake Light Switch: Service and Repair The stop light switch has a slip fit in the mounting sleeve which permits positive adjustment by pulling the brake pedal up firmly against the stop. The pedal arm forces the switch body to slip in the mounting sleeve bushing to position the switch properly. 1. Disconnect wires from switch and remove switch from bracket. 2. Position replacement switch in bracket and push inward until fully seated. Brake pedal arm moves switch to correct distance on rebound. Check if pedal is in full return position by lifting slightly by hand. 3. Connect switch electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 518 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 519 Door Switch: Locations Door Jamb Switch, RH Front Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 520 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 521 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Headlamp Dimmer Switch > Component Information > Locations Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector Twilight Sentinel Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 529 Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 530 Headlamp Switch: Locations Twilight Sentinel/Daytime Running Lamps Harness Back View Of RH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 531 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Page 532 Headlamp Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Page 533 Headlamp Switch: Service and Repair Fig. 7 Headlamp Switch Replacement 1. Disconnect battery ground cable. 2. Remove lower steering column trim panel attaching screws, then pull downward to remove. 3. Through glove compartment, unsnap righthand molding. 4. Loosen steering column support bracket to instrument panel carrier attaching bolts. Do not remove bolts. 5. Gently lower steering column assembly. Use extreme care when lowering steering to prevent damage to column assembly. 6. Remove lefthand trim plate to instrument panel carrier assembly six attaching screws, then unsnap lefthand trim assembly. 7. Remove headlamp switch attaching screws. 8. Pull switch rearward, then disconnect switch electrical connectors and remove, Fig. 7. 9. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Horn Switch > Component Information > Locations Steering Wheel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch Trunk Lid With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch > Page 541 Rear Luggage Compartment With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch > Page 542 Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations Turn Signal Switch: Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 546 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 547 C210: Turn Signal Switch Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 548 Turn Signal Switch: Service and Repair Fig. 9 Lock Plate Retaining Ring Removal Fig. 10 Turn Signal Electrical Connector & Wiring Isolation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 549 Fig. 11 Turn Signal Switch Removal From Column Bowl Fig. 12 Turn Signal Switch Replacement 1. Disconnect battery cable, then remove steering wheel and column to instrument panel trim cover. 2. On models with telescoping column, remove bumper spacer and snap ring retainer. 3. On models less telescoping column, remove cover from lock plate. 4. On all models, using a suitable tool, compress lock plate (horn contact carrier on tilt models) and remove snap ring (C-ring on tilt models), Fig. 9. 5. Remove lock plate, cancelling cam, upper bearing preload spring, thrust washer and signal lever. 6. Remove turn signal lever or actuating arm screw, if equipped, or on models with column mounted wiper switch, pull lever straight out of detent. Depress hazard warning button, then unscrew button. 7. Pull connector from bracket and wrap upper part of connector with tape to prevent snagging wires during removal, Fig. 10. 8. On Tilt models, position shifter housing in Low position. Remove harness cover. 9. On models less tilt remove retaining screws and remove switch, Fig. 11 AND 12. 10. Reverse procedure to install Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 556 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 559 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 560 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 561 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 562 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 563 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 564 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 565 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 566 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 567 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 568 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 569 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 570 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 571 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 572 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 573 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 574 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 575 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 576 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 577 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 578 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 579 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 580 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 581 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 582 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 583 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 584 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 585 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 586 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 587 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 588 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 589 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 590 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 591 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 592 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 597 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 598 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 599 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 600 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 601 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 602 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 603 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 604 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 605 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 606 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 607 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 608 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 609 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 610 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 611 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 612 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 613 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 614 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 615 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 616 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 617 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 618 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 619 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 620 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 621 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 622 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 623 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 624 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 625 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 626 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 627 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications Coolant Temperature Sensor/Switch (For Computer): Specifications Engine Coolant Temperature (ECT) Sensor ................................................................................................................................................ 23 Nm (17 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 631 Coolant Temperature Sensor/Switch (For Computer): Locations Left Front Of Engine The engine coolant temperature sensor is located near water pump. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 632 Coolant Temperature Sensor/Switch (For Computer): Description and Operation Engine Coolant Temperature Sensor The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) immersed in the engine coolant stream. Low coolant temperature produces a high resistance while high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the ECT through a resistor in the PCM and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage. the PCM knows the engine coolant temperature. Engine coolant temperature affects most systems the PCM controls. A failure in the ECT circuit should set either a Diagnostic Trouble Code (DTC) 14 or 15. Remember these DTCs indicate a failure in the engine coolant temperature sensor circuit, so proper use of the chart will lead to either repairing a wiring problem or replacing the sensor to properly repair a problem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 633 Coolant Temperature Sensor/Switch (For Computer): Service and Repair Engine Coolant Temperature Sensor IMPORTANT: Care must be taken when handling engine coolant (ECT) temperature sensor. Damage to engine coolant sensor will affect proper operation of the fuel injection system. REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Relieve coolant pressure. 3. Electrical connector. 4. Carefully back out sensor. INSTALL OR CONNECT 1. Coat threads with sealer. 2. Install sensor in engine. 3. Torque to 23 Nm (17 ft lb). 4. Connect electrical connector. 5. Refill lost coolant. 6. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 638 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 639 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 640 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 641 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 642 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 643 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 644 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 645 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 646 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 647 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 648 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 649 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 650 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 651 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 652 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 653 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 654 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 655 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 656 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 657 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 658 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 659 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 660 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 661 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 662 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 663 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 664 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 665 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 666 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 667 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 668 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Specifications Intake Air Temperature Sensor: Specifications Torque Valve Torque Valve Induction Air Sensor 44 in.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor Intake Air Temperature Sensor: Locations IAT Sensor The Intake Air Temperature (IAT) sensor is located in the air ducting, just forward of the throttle body assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 674 Intake Air Temperature Sensor: Locations Intake Air Temperature (IAT) Sensor Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 675 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions Intake Air Temperature Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 678 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 679 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 680 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 681 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 682 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 683 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 684 Intake Air Temperature Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 685 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 686 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 687 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 688 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 689 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 690 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 691 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 692 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 693 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 694 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 695 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 696 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 697 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 698 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 699 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 700 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 701 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 702 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 703 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 704 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 705 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 706 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 707 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 708 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 709 Intake Air Temperature (IAT) Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 710 Intake Air Temperature Sensor: Description and Operation Engine Coolant Temperature (ECT) Sensor The Intake Air Temperature (IAT) sensor is a thermistor (a resistor which changes value based on temperature). It is mounted in the air intake duct. Low temperature produces a high resistance and high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the sensor through a resistor in the PCM and measures the voltage. The voltage will be high when the intake air is cold, and low when the intake manifold air is hot. By measuring the voltage, the PCM knows the intake air temperature. A failure in the IAT sensor circuit should set either a DTC 23 or DTC 25. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 711 Intake Air Temperature Sensor: Service and Repair REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Electrical connector. 3. Carefully remove sensor from air duct. INSTALL OR CONNECT 1. Install sensor in engine. 2. Connect electrical connector. 3. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations > Page 717 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 720 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 721 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 722 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 723 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 724 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 725 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 726 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 727 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 728 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 729 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 730 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 731 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 732 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 733 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 734 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 735 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 736 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 737 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 738 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 739 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 740 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 741 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 742 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 743 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 744 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 745 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 746 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 747 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 748 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 749 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 750 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 751 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 752 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 753 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 754 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications MAP Sensor Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications > Page 759 Manifold Pressure/Vacuum Sensor: Mechanical Specifications Manifold Absolute Pressure (MAP) Bolt ...................................................................................................................................................... 6 Nm (50 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Page 760 Manifold Pressure/Vacuum Sensor: Locations MAP Sensor Location Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions Manifold Pressure/Vacuum Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 763 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 764 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 765 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 766 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 767 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 768 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 769 Manifold Pressure/Vacuum Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 770 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 771 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 772 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 773 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 774 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 775 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 776 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 777 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 778 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 779 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 780 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 781 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 782 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 783 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 784 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 785 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 786 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 787 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 788 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 789 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 790 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 791 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 792 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 793 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 794 Map Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 795 Manifold Pressure/Vacuum Sensor: Description and Operation MAP Sensor The Manifold Absolute Pressure (MAP) sensor is a pressure sensor that measures changes in intake manifold pressure. The pressure changes as a result of engine load and speed. The MAP sensor converts this to a voltage output. A closed throttle on engine coastdown would produce a relatively low MAP output while a wide-open throttle would produce a high MAP output voltage. This high output voltage is produced because the pressure inside the manifold is the same as outside the manifold, so you measure 100% of outside air pressure. Manifold Absolute Pressure (MAP) is inversely proportional to what you would measure on a vacuum gage. When manifold pressure is high vacuum is low. The MAP sensor is also used to measure barometric pressure under certain conditions which allows the Powertrain Control Module (PCM) to automatically adjust for different altitudes. The PCM sends a 5 volt reference signal to the MAP sensor. As the manifold pressure changes the electrical resistance of the MAP sensor also changes. By monitoring the sensor output voltage the PCM knows the manifold pressure. The PCM uses the MAP sensor to control ignition timing. The MAP sensor is also used for speed density fuel management. When the PCM detects a malfunction with the Mass Air Flow (MAF) sensor circuit the PCM will default to speed density. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 796 Manifold Pressure/Vacuum Sensor: Service and Repair MAP Sensor Location REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Resonator. 3. Electrical connector. 4. Hold down bolts (2). 5. Sensor from intake manifold. INSTALL OR CONNECT 1. New sensor seal (lightly coated with clean engine oil). 2. Sensor into intake manifold. 3. Hold down bolts. 4. Torque to 6 Nm (50 lb in). 5. Connect electrical connector. 6. Resonator. 7. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Technical Service Bulletins > Oxygen Sensors - Silica Contamination Oxygen Sensor: Technical Service Bulletins Oxygen Sensors - Silica Contamination Model Year: 1981 Bulletin No: 81-I-37 File In Group: 60 Number: 11 Date: Feb. 81 Subject: Silica Contamination of Oxygen Sensors and Gelation of Oil. Models Affected: All Oxygen sensor performance can deteriorate if certain RTV silicone gasket materials are used. Other RTV's when used with certain oils, may cause gelation of the oil. The degree of performance severity depends on the type of RTV and application of the engine involved. Therefore, when repairing engines where this item is involved, it is important to use either cork composition gaskets or RTV silicone gasket material approved for such use. GMS (General Motors Sealant) or equivalent material can be used. GMS is available through GMPD with the following part numbers: 1052366 3 oz. 1052434 10.14 oz. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications Oxygen Sensor Output Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications > Page 803 Oxygen Sensor: Mechanical Specifications Heated Oxygen Sensor (HO2S) .......................................................................................................... ......................................................... 41 Nm (30 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH Engine, Left Side Lower Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 806 Lower Right Side Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 807 HO2S Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions Oxygen Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 810 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 811 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 812 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 813 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 814 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 815 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 816 Oxygen Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 817 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 818 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 819 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 820 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 821 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 822 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 823 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 824 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 825 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 826 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 827 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 828 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 829 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 830 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 831 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 832 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 833 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 834 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 835 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 836 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 837 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 838 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 839 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 840 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 841 Oxygen Sensor: Electrical Diagrams Heated Oxygen Sensor (HO2S) Sensor Circuit. Right Heated Oxygen Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 842 Oxygen Sensor: Description and Operation HO2S Cutaway Oxygen Sensor Element The Heated Oxygen Sensor (HO2S) is essentially a small variable battery; it has the ability to produce a low voltage signal that feeds information on engine exhaust oxygen content to the Powertrain Control Module (PCM). The PCM sends a reference signal of 450 mV. The reference signal serves to run the engine when it is in "Open Loop" mode of operation. When the air/fuel ratio is correct the PCM displays 450 mV. When the engine is operating with a rich air/fuel ratio, there is a reduction of free oxygen in the exhaust stream and the oxygen voltage rises above the reference voltage. The HO2S is constructed from a material (zirconia/platinum) that conducts electricity under certain conditions. At operating temperature, 315°C (60o° F), the element becomes a semiconductor. A platinum coating on the outer surface of the element stimulates further combustion of the exhaust gases right Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 843 at the surface and this helps keep the element up to the desired temperature. The HO2S has an inter cavity which is filled with atmospheric (reference) air. The reference air has approximately 21% oxygen in it. In this electrical circuit this inter cavity is the positive (+) terminal. The outer surface of the element is exposed to the exhaust gas stream. It is the negative (-) or ground terminal. The oxygen concentration differences between the reference air and exhaust gases produce small voltages. A rich exhaust (excessive fuel) has almost no oxygen. When there is a large difference in the amount of oxygen touching the inside and outside surfaces, there is more conduction, and the sensor puts out a voltage signal above 600 mV. With lean exhaust (excessive oxygen) there is about two percent oxygen in the exhaust. This is a smaller difference in oxygen from the outside surfaces which results in less conduction and a voltage signal below 300 mV. The voltages are monitored and used by the PCM to "fine tune" the air/fuel ratio to achieve the ideal mixture desired. When the engine is running lean. the voltage drops below the reference voltage due to excess oxygen in the exhaust stream. The HO2S provides the feedback information for the "Closed Loop" operating mode of the fuel delivery system. The HO2S indicates to the PCM what is happening in the exhaust. It does not cause things to happen. It is a type of gage: Low voltage output = lean mixture = high oxygen content in exhaust; high voltage output = rich mixture = low oxygen content in the exhaust. An open Heated Oxygen Sensor (HO2S) circuit, should set Diagnostic Trouble Code (DTC) 13 or 63. A constant low voltage in the HO2S circuit could set a DTC 44 or 64. A constant high voltage in the circuit should set a DTC 45 or 65. DTCs 44. 45. 64, or 65 could also be set as a result of fuel system problems. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 844 Oxygen Sensor: Service and Repair HO2S Location CAUTION: The Heated Oxygen Sensor (HO2S) uses a permanently attached pigtail and connector. This pigtail should not be removed from the oxygen sensor. Damage or removal of the pigtail or connector could affect proper operation of the oxygen sensor. ^ Take care when handling the oxygen sensor. The in-line electrical connector and louvered end must be kept free off grease, dirt or other contaminants. Also, avoid using cleaning solvents of any type. Be careful not to subject the sensor to sharp impact. REMOVAL: NOTICE: The HO2S may be difficult to remove when engine temperature is below 48° C (120° F). Excessive force may damage threads in exhaust pipe. 1. Disconnect the negative battery cable. 2. Raise vehicle. 3. Disconnect the oxygen sensor electrical connector. 4. Carefully remove the oxygen sensor. INSTALLATION: NOTICE: A special anti-seize compound is used on the oxygen sensor threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will already have the compound applied to the threads. If a sensor is removed from an engine, and, if for any reason it is to be reinstalled, the threads must have anti-seize compound applied before reinstallation. 1. Coat the threads of the HO2S with anti-seize compound P/N 5613695, or equivalent if necessary. 2. Install the sensor in the engine, and tighten to 41 Nm (30 ft lb). 3. Connect the electrical connector. 4. Lower vehicle. 5. Connect the negative battery cable. NOTICE: The system has a learning ability which allows it to make corrections for minor variations in the fuel system to improve driveability. When the battery is disconnected the computer's memory is cleared and the learning process has to begin all over again. A change may be noticed in the driving performance of the vehicle. To reset the vehicles learning ability, make sure the engine is at operating temperature and operate the vehicle at part throttle, moderate acceleration, and idle conditions, until normal performance returns. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Locations Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions Power Steering Pressure Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 850 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 851 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 852 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 853 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 854 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 855 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 856 Power Steering Pressure Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 857 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 858 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 859 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 860 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 861 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 862 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 863 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 864 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 865 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 866 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 867 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 868 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 869 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 870 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 871 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 872 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 873 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 874 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 875 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 876 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 877 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 878 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 879 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 880 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 881 Power Steering Pressure Switch Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Page 882 Power Steering Pressure Switch: Description and Operation This switch informs the PCM when the power steering pressure is high. During high pressure conditions, the Powertrain Control Module (PCM) will increase idle speed to compensate for the additional load. When the switch closes, the PCM will increase idle speed to compensate for the additional load. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 886 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 887 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 890 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 891 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 892 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 893 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 894 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 895 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 896 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 897 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 898 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 899 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 900 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 901 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 902 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 903 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 904 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 905 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 906 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 907 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 908 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 909 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 910 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 911 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 912 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 913 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 914 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 915 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 916 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 917 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 918 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 919 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 920 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 921 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 922 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 923 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 928 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 929 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 932 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 933 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 934 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 935 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 936 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 937 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 938 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 939 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 940 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 941 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 942 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 943 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 944 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 945 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 946 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 947 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 948 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 949 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 950 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 951 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 952 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 953 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 954 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 955 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 956 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 957 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 958 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 959 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 960 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 961 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 962 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 963 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 964 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Locations Rear Of Transmission Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions Vehicle Speed Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 970 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 971 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 972 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 973 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 974 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 975 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 976 Vehicle Speed Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 977 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 978 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 979 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 980 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 981 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 982 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 983 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 984 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 985 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 986 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 987 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 988 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 989 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 990 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 991 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 992 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 993 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 994 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 995 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 996 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 997 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 998 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 999 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1000 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description Vehicle Speed Sensor: Description and Operation General Description Vehicle Speed Sensor (2WD) The Vehicle Speed Sensor (VSS) is a pulse counter type input that informs the Powertrain Control Module (PCM) how fast the vehicle is being driven. The VSS system uses an inductive sensor mounted in the tail housing of the transmission and a toothed reluctor wheel on the tail shaft. As the reluctor rotates, the teeth alternately interfere with the magnetic field of the sensor creating an induced voltage pulse. The VSS produces an AC voltage signal that increases with vehicle speed. The PCM processes this signal and sends it to the instrument panel, EVO module, chime module and cruise control module on CKT 817. A malfunction in the VSS system could set Diagnostic Trouble Code (DTC) 24 or DTC 72. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description > Page 1003 Vehicle Speed Sensor: Description and Operation Circuit Operation The Speed Sensor Circuit consists of a magnetic type sensor and wiring. Gear teeth pressed on the Transmission Output Shaft induce an alternating current in the sensor. This sensor generates a sine wave output with a frequency proportional to vehicle speed. The Powertrain Control Module (PCM) converts this signal to an output that is switched to ground at a frequency of 4000 pulses per mile at the DK GRN/WHT wire (CKT 817) which feeds the Turn Signal Alarm, Power Steering Control Module, Instrument Cluster, Cruise Control Module and Radio (Chev only). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Vehicle Speed Sensor: Initial Inspection and Diagnostic Overview PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 1006 Vehicle Speed Sensor: Symptom Related Diagnostic Procedures Chart #1 Speedometer And Cruise Control Inoperative; Code 24 Not Set Symptom Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 1012 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1015 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1016 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1017 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1018 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1019 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1020 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1021 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1022 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1023 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1024 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1025 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1026 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1027 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1028 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1029 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1030 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1031 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1032 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1033 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1034 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1035 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1036 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1037 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1038 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1039 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1040 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1041 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1042 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1043 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1044 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1045 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1046 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 1047 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 1048 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Specifications Oil Pressure Switch (For Fuel Pump): Specifications Fuel Pump Switch and Engine Oil Pressure Sensor ................................................................................................................................... 12 Nm (106 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch > Page 1054 Oil Pressure Switch (For Fuel Pump): Locations Oil Pressure Sensor/Fuel Pump Switch Fuel Pump - Oil Pressure Switch The sensor is threaded into a TEE fitting at the rear of the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions Oil Pressure Switch (For Fuel Pump): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1057 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1058 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1059 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1060 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1061 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1062 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1063 Oil Pressure Switch (For Fuel Pump): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1064 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1065 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1066 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1067 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1068 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1069 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1070 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1071 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1072 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1073 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1074 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1075 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1076 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1077 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1078 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1079 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1080 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1081 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1082 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1083 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1084 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1085 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1086 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1087 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1088 Fuel Pump Switch/Engine Oil Pressure Gage Sensor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 1089 Fuel Pump Relay Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 1090 Oil Pressure Switch (For Fuel Pump): Description and Operation Fuel Pump - Oil Pressure Switch As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 1091 Oil Pressure Switch (For Fuel Pump): Service and Repair Fuel Pump - Oil Pressure Switch REMOVE OR DISCONNECT 1. Disconnect electrical connector. 2. Fuel pump switch and oil pressure sensor. INSTALL OR CONNECT 1. Fuel pump switch and oil pressure sensor. 2. Tighten to 12 Nm (106 lb in.) 3. Electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 1095 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 1096 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1099 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1100 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1101 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1102 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1103 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1104 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1105 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1106 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1107 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1108 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1109 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1110 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1111 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1112 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1113 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1114 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1115 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1116 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1117 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1118 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1119 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1120 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1121 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1122 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1123 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1124 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1125 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1126 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1127 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1128 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1129 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1130 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 1131 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 1132 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1138 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1139 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1140 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1141 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1142 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1143 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1144 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1145 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1146 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1147 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1148 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1149 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1150 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1151 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1152 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1153 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1154 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1155 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1156 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1157 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1158 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1159 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1160 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1161 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1162 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1163 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1164 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1165 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1166 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1167 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1168 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1173 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1174 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1175 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1176 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1177 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1178 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1179 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1180 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1181 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1182 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1183 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1184 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1185 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1186 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1187 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1188 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1189 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1190 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1191 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1192 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1193 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1194 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1195 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1196 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1197 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1198 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1199 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1200 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1201 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1202 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1203 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Locations > Component Locations > Page 1209 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1212 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1213 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1214 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1215 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1216 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1217 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1218 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1219 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1220 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1221 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1222 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1223 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1224 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1225 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1226 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1227 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1228 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1229 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1230 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1231 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1232 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1233 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1234 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1235 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1236 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1237 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1238 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1239 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1240 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1241 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1242 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 1243 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 1244 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 1245 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 1246 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Restraint Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations LH Radiator Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Restraint Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations > Page 1251 Discriminating Sensors and Arming Sensors: Description and Operation DESCRIPTION The discriminating and arming sensors are used by the SIR system to determine whether or not certain frontal crashes require deployment of the air bags. OPERATION The sensor consists of a sensing element, normally open switch contacts and a diagnostic resistor. The sensing element closes the switch contacts when the vehicle velocity changes are severe enough to warrant air bag deployment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Restraint Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations > Page 1252 Discriminating Sensors and Arming Sensors: Service and Repair WARNING: The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. LEFT SENSOR 1. Disarm system as described in Air Bag System Disarming & Arming 2. Remove Connector Position Assurance (CPA), then disconnect sensor electrical connector. 3. Remove sensor mounting bolts, then the sensor. 4. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition key to the On position and verify the AIR BAG or SIR warning lamp flashes seven to nine times, then turns off. If warning lamp does not operate as specified, refer to Testing & Inspection. RIGHT SENSOR 1. Disarm system as described in Air Bag System Disarming & Arming. 2. Remove battery, then the Connector Position Assurance (CPA). 3. Disconnect sensor electrical connector. 4. Remove sensor mounting bolts, then the sensor. 5. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition key to the On position and verify the AIR BAG or SIR warning lamp flashes seven to nine times, then turns off. If warning lamp does not operate as specified, refer to System Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Restraint Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Restraint Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations > Page 1257 Seat Belt Buckle Switch: Connector Locations Cross Car Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Restraint Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations > Page 1258 Cross Car Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Restraint Systems > Seat Occupant Sensor > Component Information > Technical Service Bulletins > Restraints - Passenger Presence System Information Seat Occupant Sensor: Technical Service Bulletins Restraints - Passenger Presence System Information INFORMATION Bulletin No.: 06-08-50-009F Date: December 23, 2010 Subject: Information on Passenger Presence Sensing System (PPS or PSS) Concerns With Custom Upholstery, Accessory Seat Heaters or Other Comfort Enhancing Devices Models: 2011 and Prior GM Passenger Cars and Trucks Equipped with Passenger Presence Sensing System Supercede: This bulletin is being revised to update the model years. Please discard Corporate Bulletin Number 06-08-50-009E (Section 08 - Body and Accessories). Concerns About Safety and Alterations to the Front Passenger Seat Important ON A GM VEHICLE EQUIPPED WITH A PASSENGER SENSING SYSTEM, USE THE SEAT COVERS AND OTHER SEAT-RELATED EQUIPMENT AS RELEASED BY GM FOR THAT VEHICLE. DO NOT ALTER THE SEAT COVERS OR SEAT-RELATED EQUIPMENT. ANY ALTERATIONS TO SEAT COVERS OR GM ACCESSORIES DEFEATS THE INTENDED DESIGN OF THE SYSTEM. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER SEAT ALTERATIONS, INCLUDING ANY WARRANTY REPAIRS INCURRED. The front passenger seat in many GM vehicles is equipped with a passenger sensing system that will turn off the right front passenger's frontal airbag under certain conditions, such as when an infant or child seat is present. In some vehicles, the passenger sensing system will also turn off the right front passenger's seat mounted side impact airbag. For the system to function properly, sensors are used in the seat to detect the presence of a properly-seated occupant. The passenger sensing system may not operate properly if the original seat trim is replaced (1) by non-GM covers, upholstery or trim, or (2) by GM covers, upholstery or trim designed for a different vehicle or (3) by GM covers, upholstery or trim that has been altered by a trim shop, or (4) if any object, such as an aftermarket seat heater or a comfort enhancing pad or device is installed under the seat fabric or between the occupant and the seat fabric. Aftermarket Seat Heaters, Custom Upholstery, and Comfort Enhancing Pads or Devices Important ON A GM VEHICLE EQUIPPED WITH A PASSENGER SENSING SYSTEM, USE ONLY SEAT COVERS AND OTHER SEAT-RELATED EQUIPMENT RELEASED AS GM ACCESSORIES FOR THAT VEHICLE. DO NOT USE ANY OTHER TYPE OF SEAT COVERS OR SEAT-RELATED EQUIPMENT, OR GM ACCESSORIES RELEASED FOR OTHER VEHICLE APPLICATIONS. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER SEAT ACCESSORIES, INCLUDING ANY WARRANTY REPAIRS MADE NECESSARY BY SUCH USE. Many types of aftermarket accessories are available to customers, upfitting shops, and dealers. Some of these devices sit on top of, or are Velcro(R) strapped to the seat while others such as seat heaters are installed under the seat fabric. Additionally, seat covers made of leather or other materials may have different padding thickness installed that could prevent the Passenger Sensing System from functioning properly. Never alter the vehicle seats. Never add pads or other devices to the seat cushion, as this may interfere with the operation of the Passenger Sensing System and either prevent proper deployment of the passenger airbag or prevent proper suppression of the passenger air bag. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions Neutral Safety Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1268 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1269 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1270 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1271 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1272 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1273 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1274 Neutral Safety Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1275 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1276 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1277 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1278 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1279 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1280 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1281 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1282 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1283 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1284 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1285 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1286 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1287 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1288 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1289 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1290 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1291 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1292 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1293 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1294 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1295 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1296 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1297 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1298 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Page 1299 Neutral Safety Switch: Service and Repair Fig. 4 Mechanical Neutral Safety System. Tilt Column Fig. 5 Mechanical Neutral Safety System. Standard Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Page 1300 Fig. 6 Mechanical Neutral Safety System In Park Position MECHANICAL Actuation of the ignition switch is prevented by a mechanical lockout system Fig. 4 AND 5,. which prevents the lock cylinder from rotating when the selector lever is out of Park or Neutral. When the selector lever is in Park or Neutral, the slots in the bowl plate and the finger on the actuator rod align, allowing the finger to pass through the bowl plate in turn actuating the ignition switch, Fig. 6. If the selector lever is in any position other than Park or Neutral, the finger contacts the bowl plate when the lock cylinder is rotated, thereby preventing full travel of the lock cylinder. ELECTRIC On models incorporating an electric neutral start switch, the start switch, back-up light switch and parking brake vacuum release valve are combined into one unit. This unit is mounted on the steering column under the instrument panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Locations Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions Power Steering Pressure Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1308 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1309 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1310 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1311 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1312 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1313 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1314 Power Steering Pressure Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1315 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1316 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1317 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1318 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1319 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1320 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1321 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1322 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1323 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1324 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1325 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1326 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1327 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1328 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1329 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1330 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1331 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1332 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1333 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1334 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1335 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1336 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1337 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1338 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 1339 Power Steering Pressure Switch Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Page 1340 Power Steering Pressure Switch: Description and Operation This switch informs the PCM when the power steering pressure is high. During high pressure conditions, the Powertrain Control Module (PCM) will increase idle speed to compensate for the additional load. When the switch closes, the PCM will increase idle speed to compensate for the additional load. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations Center Of Rear Crossmember Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 1345 Ride Height Sensor: Description and Operation DESCRIPTION The height sensor controls two circuits, compressor relay coil ground circuit and exhaust solenoid coil ground circuit. To prevent energizing the compressor relay and exhaust solenoid circuits during normal ride motions, the sensor circuit provides a predetermined delay before the ground circuit is completed. The sensor electronically limits compressor run time and exhaust solenoid energized time. This limit function is necessary to prevent continuous compressor operation in case of a system leak or continuous exhaust solenoid operation. This timer is reset whenever the ignition is turned Off and On, or height sensor exhaust or compressor signal changes. The height sensor is mounted to the body frame in the rear of the vehicle. The sensor actuator arm is attached to the control arm by a short link Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 1346 Ride Height Sensor: Testing and Inspection CAUTION: When diagnostic procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Turn ignition Off, then On. This will reset height sensor timer circuits. 2. Raise vehicle on hoist. Ensure rear wheels or axle housing are supported and that vehicle is at proper trim height. 3. Disconnect link from height sensor arm, then ensure sensor wiring and harness ground are connected properly. 4. Move sensor arm upward. There should be a delay of 8-15 seconds before compressor turns on and shocks start to inflate. As soon as shocks start to fill, stop compressor by moving sensor arm down. 5. Move sensor arm down below position where compressor stopped. There should be a delay of 8-15 seconds before shocks start to deflate and vehicle lowers. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 1347 Ride Height Sensor: Adjustments ADJUSTMENTS The link should be properly attached to the sensor arm and track bar, when making this adjustment. 1. Loosen lock bolt securing metal arm to height sensor plastic arm. 2. To raise vehicle trim height, move plastic arm upward and tighten lock bolt. 3. To lower vehicle trim height, loosen lock bolt securing metal arm to height sensor plastic arm, then move plastic arm down. 4. If adjustment cannot be made, check for correct sensor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 1348 Ride Height Sensor: Service and Repair WARNING: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Disconnect battery ground cable. 2. Raise and support vehicle. 3. Disconnect harness from sensor electrical connector by squeezing oval sides of the connector lock to release locking tabs. 4. Remove link from height sensor arm, then remove sensor mounting screws or nuts and the sensor. 5. Remove sensor mounting bracket to underbody attaching screws and remove bracket. 6. Reverse procedure to install, noting the following: a. When connecting harness to sensor electrical connector, push connector into sensor plug until sloped shoulder on rear edge of boss is visible in plug slot. Push oval connector lock onto plug until its two locking tabs snap over shoulder of sensor plug. b. Perform height sensor operational check and adjustment procedure as described under Testing and Inspection. See: Testing and Inspection Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 1355 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 1356 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1359 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1360 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1361 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1362 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1363 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1364 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1365 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1366 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1367 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1368 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1369 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1370 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1371 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1372 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1373 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1374 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1375 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1376 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1377 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1378 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1379 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1380 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1381 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1382 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1383 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1384 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1385 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1386 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1387 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1388 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1389 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1390 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 1391 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Temperature Sensor/Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1396 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1397 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1398 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1399 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1400 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1401 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1402 Transmission Temperature Sensor/Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1403 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1404 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1405 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1406 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1407 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1408 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1409 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1410 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1411 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1412 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1413 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1414 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1415 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1416 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1417 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1418 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1419 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1420 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1421 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1422 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1423 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1424 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1425 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1426 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 1427 Transmission Range Switch Assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Page 1428 Transmission Temperature Sensor/Switch: Description and Operation The Transmission Fluid Temperature (TFT) sensor is a thermistor (a device that changes resistance according to changes in temperature) used to indicate transmission fluid temperature. High sensor resistance produces high signal input voltage which corresponds to low fluid temperature. Low sensor resistance produces low signal input voltage which corresponds to high fluid temperature. The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following: ^ Torque Converter Clutch (TCC) apply and release schedules. ^ Hot mode determination. ^ Shift quality. The TFT sensor is part of the transmission range fluid pressure switch assembly and is attached to the control valve body within the transmission. A fault in the Transmission Fluid Temperature (TFT) sensor circuit will set a DTC 58. 59 or 79. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Heated Glass Element Switch > Component Information > Diagrams Rear Defogger Control Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations Power Window Switch: Component Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 1437 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 1438 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 1439 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 1440 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 1441 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Page 1442 Power Window Switch: Diagrams Master Power Window Switch Assembly C1 and C2 Power Window Switch LH And RH Rear RH Front Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Washer Fluid Level Switch > Component Information > Locations LH Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations Windshield Washer Switch: Component Locations Upper LH Side Of Steering Column LH I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations > Page 1451 Windshield Washer Switch: Connector Locations Lower LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations > Page 1452 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Page 1453 C216: Windshield Wiper/Washer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations Wiper Switch: Component Locations Upper LH Side Of Steering Column LH I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations > Page 1458 Wiper Switch: Connector Locations Lower LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations > Page 1459 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 1460 C216: Windshield Wiper/Washer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 1461 Wiper Switch: Service and Repair Fig. 18 Windshield Wiper Switch. Standard Steering Column Fig. 19 Windshield Wiper Switch. Tilt Steering Column Fig. 20 Windshield Wiper Switch Actuator Pivot Pin Replacement 1. Disconnect battery ground cable and remove turn signal switch as outlined under Turn Signal Switch, Service and Repair. See: Sensors and Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Sensors and Switches > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 1462 Switches - Lighting and Horns/Turn Signal Switch/Service and Repair 2. Remove ignition lock, ignition switch and dimmer switch as outlined under Ignition Lock, Ignition Switch and Dimmer Switch Service and Repair. See: Steering and Suspension/Steering/Steering Column/Service and Repair 3. Remove ignition lock housing retaining screws and housing, Fig.18 and 19.. 4. Remove pivot bolt and wiper switch from lock housing, Fig. 20. 5. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > Customer Interest: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening Alignment: Customer Interest Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Important: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > Customer Interest: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 1472 Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > Customer Interest: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 1473 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications Alignment: All Technical Service Bulletins Steering/Suspension - Wheel Alignment Specifications WARRANTY ADMINISTRATION Bulletin No.: 05-03-07-009C Date: December 09, 2010 Subject: Wheel Alignment Specifications, Requirements and Recommendations for GM Vehicles Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks Supercede: This bulletin is being extensively revised to provide technicians and warranty administrators with an all inclusive guide for wheel alignments. PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. Please discard Corporate Bulletin Number 05-03-07-009B (Section 03 - Suspension). Purpose The purpose of this bulletin is to provide retail, wholesale and fleet personnel with General Motors' warranty service requirements and recommendations for customer concerns related to wheel alignment. For your convenience, this bulletin updates and centralizes all of GM's Standard Wheel Alignment Service Procedures, Policy Guidelines and bulletins on wheel alignment warranty service. Important PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. The following five (5) key steps are a summary of this bulletin and are REQUIRED in completing a successful wheel alignment service. 1. Verify the vehicle is in an Original Equipment condition for curb weight, tires, wheels, suspension and steering configurations. Vehicles modified in any of these areas are not covered for wheel alignment warranty. 2. Review the customer concern relative to "Normal Operation" definitions. 3. Verify that vehicle is within the "Mileage Policy" range. 4. Document wheel alignment warranty claims appropriately for labor operations E2000 and E2020. The following information must be documented or attached to the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 5. Use the proper wheel alignment equipment (preferred with print-out capability), process and the appropriate calibration maintenance schedules. Important If it is determined that a wheel alignment is necessary under warranty, use the proper labor code for the repair. E2000 for Steering Wheel Angle and/or Front Toe set or E2020 for Wheel Alignment Check/Adjust includes Caster, Camber and Toe set (Wheel alignment labor time for other component repairs is to be charged to the component that causes a wheel alignment operation.). The following flowchart is to help summarize the information detailed in this bulletin and should be used whenever a wheel alignment is performed. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1479 Verify Original Equipment Condition of the Vehicle - Verify that Original Equipment Tires and Wheels or Official GM Accessory Tires and Wheels are on the vehicle. - Verify that aftermarket suspension "Lift" or "Lowering" Kits or other suspension alterations have NOT been done to the vehicle. - Check for accidental damage to the vehicle; for example, severe pothole or curb impacts, collision damage that may have affected the wheel alignment of the vehicle; e.g., engine cradles, suspension control arms, axles, wheels, wheel covers, tires may show evidence of damage/impact. - Check to be sure vehicle has seen "Normal Use" rather than abuse; e.g., very aggressive driving may show up by looking at the tires and condition of the vehicle. - Check for other additional equipment items that may significantly affect vehicle mass such as large tool boxes, campers, snow plow packages (without the snowplow RPO), etc., especially in trucks and cutaway/incomplete vehicles. Significant additional mass can affect trim height and wheel alignment of the vehicle and may necessitate a customer pay wheel alignment when placed semi-permanently in the vehicle (Upfitter instructions are to realign the vehicle after placement of these types of items. (This typically applies to trucks and incomplete vehicles that can be upfit with equipment such as the above.) Customer Concerns, "Normal Operation" Conditions and "Mileage Policy" Possible Concerns The following are typical conditions that may require wheel alignment warranty service: 1. Lead/Pull: defined as "at a constant highway speed on a typical straight road, the amount of effort required at the steering wheel to maintain the vehicle's straight heading." Important Please evaluate for the condition with hands-on the steering wheel. Follow the "Vehicle Leads/Pulls" diagnostic tree located in SI to determine the cause of a lead/pull concern. Lead/Pull concerns can be due to road crown or road slope, tires, wheel alignment or even in rare circumstances a steering gear issue. Lead/pull concerns due to road crown are considered "Normal Operation" and are NOT a warrantable condition -- the customer should be advised that this is "Normal Operation." Important Some customers may comment on a "Lead/Pull" when they hold the steering wheel in a level condition. If so, this is more likely a "steering wheel angle" concern because the customer is "steering" the vehicle to obtain a "level" steering wheel. 2. Steering wheel angle to the left or right (counter-clockwise or clockwise, respectively): Defined as the steering wheel angle (clocking) deviation from "level" while maintaining a straight heading on a typical straight road. 3. Irregular or Premature tire wear: Slight to very slight "feathering" or "edge" wear on the shoulders of tires is NOT considered unusual and should even out with a tire rotation; if the customer is concerned about a "feathering" condition of the tires, the customer could be advised to rotate the tires earlier than the next scheduled mileage/maintenance interval (but no later than the next interval). Be sure to understand the customer's driving habits as this will also heavily influence the tire wear performance; tire wear from aggressive or abusive driving habits is NOT a warrantable condition. Important Slight or mild feathering, cupping, edge or heel/toe wear of tire tread shoulders is "normal" and can show up very early in a tire/vehicle service mileage; in fact, some new tires can show evidence of feathering from the factory. These issues do NOT affect the overall performance and tread life of the tire. Dealer personnel should always check the customer's maintenance records to ensure that tire inflation pressure is being maintained to placard and that the tires are being rotated (modified-X pattern) at the proper mileage intervals. Wheel alignments are NOT to be performed for the types of "Normal" Tire Feathering shown in Figures 1-4 below. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1480 Figure 1: Full Tread View - "NORMAL" Tire "Feathering" Wear on the Shoulder/Adjacent/Center Ribs Figure 2: Tire Shoulder View Example 1 - "NORMAL" Tire "Feathering" Wear on the Shoulder Figure 3: Tire Shoulder View Example 2 - "NORMAL" Tire "Feathering" Wear Figure 4: Detail Side View of Tire Shoulder Area - "NORMAL" Tire "Feathering" Wear Important When a wheel alignment is deemed necessary for tire wear, be sure to document on the repair order, in as much detail as possible, the severity and type of tire wear (e.g., severe center wear or severe inside or outside shoulder wear) and the position of the tire on the vehicle (RF, LF, LR, RR). Please note the customer's concern with the wear such as, noise, appearance, wear life, etc. A field product report with pictures of the tire wear condition is recommended. Refer to Corporate Bulletin Number 02-00-89-002J and #07-00-89-036C. 4. Other repairs that affect wheel alignment; e.g., certain component replacement such as suspension control arm replacement, engine cradle adjustment/replace, steering gear replacement, steering tie rod replace, suspension strut/shock, steering knuckle, etc. may require a wheel alignment. Important If other components or repairs are identified as affecting the wheel alignment, policy calls for the wheel alignment labor time to be charged to the replaced/repaired component's labor operation time rather than the wheel alignment labor operations. Important Vibration type customer concerns are generally NOT due to wheel alignment except in the rare cases; e.g., extreme diagonal wear across the tread. In general, wheel alignments are NOT to be performed as an investigation/correction for vibration concerns. "Normal Operation" Conditions Vehicle Lead/Pull Due to Road Crown or Slope: As part of "Normal Operation," vehicles will follow side-to-side or left to right road crown or slope. Be sure to verify from the customer the types of roads they are driving as they may not recognize the influence of road crown on vehicle lead/pull and steering wheel angle. If a vehicle requires significant steering effort to prevent it from "climbing" the road crown there may be an issue to be looked into further. Important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1481 A wheel alignment will generally NOT correct vehicles that follow the road crown since this is within "Normal Operation." Mileage Policy The following mileage policy applies for E2020 and E2000 labor operations: Note Wheel Alignment is NOT covered under the New Vehicle Limited Warranty for Express and Savana Cutaway vehicles as these vehicles require Upfitters to set the wheel alignment after completing the vehicles. - 0-800 km (0-500 mi): E2000/E2020 claims ONLY allowed with Call Center Authorization. Due to the tie down during shipping, the vehicle's suspension requires some time to reach normal operating position. For this reason, new vehicles are generally NOT to be aligned until they have accumulated at least 800 km (500 mi). A field product report should accompany any claim within this mileage range. - 801-12,000 km (501-7,500 mi): - If a vehicle came from the factory with incorrect alignment settings, any resulting off-angle steering wheel, lead/pull characteristics or the rare occurrence of excessive tire wear would be apparent early in the life of the vehicle. The following policy applies: - Vehicles 100% Factory Set/Measured for Caster/Camber/Toe - Escalade/ESV/EXT, Tahoe/Suburban, Yukon/XL/Denali, Silverado/Sierra, Express/Savana, Corvette and Colorado/Canyon: E2000/E2020 Claims: Call Center Authorization Required - All Vehicles NOT 100% Factory Set/Measured for Caster/Camber/Toe as noted above: E2000/E2020 Claims: Dealer Service Manager Authorization Required - 12,001 km and beyond (7,501 miles and beyond): During this period, customers are responsible for the wheel alignment expense or dealers may provide on a case-by case basis a one-time customer enthusiasm claim up to 16,000 km (10,000 mi). In the event that a defective component required the use of the subject labor operations, the identified defective component labor operation will include the appropriate labor time for a wheel alignment as an add condition to the component repair. Important Only one wheel alignment labor operation claim (E2000 or E2020) may be used per VIN. Warranty Documentation Requirements When a wheel alignment service has been deemed necessary, the following items will need to be clearly documented on/with the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 1. Document the customer concern in as much detail as possible on the repair order and in the warranty administration system. Preferred examples: - Steering wheel is off angle in the counterclockwise direction by approximately x degrees or clocking position. - Vehicle lead/pulls to the right at approximately x-y mph. Vehicle will climb the road crown. Severe, Moderate or Slight. - RF and LF tires are wearing on the outside shoulders with severe feathering. Important In the event of a lead/pull or steering wheel angle concern, please note the direction of lead/pull (left or right) or direction of steering wheel angle (clockwise or counterclockwise) on the repair order and within the warranty claim verbatim. Important In the event of a tire wear concern, please note the position on the vehicle and where the wear is occurring on the tire; i.e., the RF tire is wearing on the inside shoulder. 2. Document the technician's findings on cause and correction of the issue. Examples: - Reset LF toe from 0.45 degrees to 0.10 degrees and RF toe from -0.25 degrees to 0.10 degrees to correct the steering wheel angle from 5 degrees counterclockwise to 0 degrees. - Reset LF camber from 0.25 degrees to -0.05 degrees to correct the cross-camber condition of +0.30 degrees to 0.00 degrees on the vehicle. - Front Sum toe was found to be 0.50 degrees, reset to 0.20 degrees. 3. Print-out the "Before" and "After" wheel alignment measurements/settings and attach them to the Repair Order or if print-out capability is not Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1482 available, measurements may also be clearly and legibly handwritten into the Wheel Alignment Repair Order Questionnaire attached to this bulletin. 4. Attach the Wheel Alignment Repair Order Questionnaire below along with the print-out of "Before" and "After" wheel alignment measurements to the Repair Order and retain for use by GM. Wheel Alignment Equipment and Process Wheel alignments must be performed with a quality machine that will give accurate results when performing checks. "External Reference" (image-based camera technology) is preferred. Please refer to Corporate Bulletin Number 05-00-89-029B: General Motors Dealership Critical Equipment Requirements and Recommendations. Requirements: - Computerized four wheel alignment system. - Computer capable of printing before and after alignment reports. - Computer capable of time and date stamp printout. - Racking system must have jacking capability - Racking system must be capable of level to 1.6 mm (1/16 in) - Appropriate wheel stops and safety certification - Built-in turn plates and slip plates - Wheel clamps capable of attaching to 20" or larger wheels - Racking capable of accepting any GM passenger car or light duty truck - Operator properly trained and ASE-certified (U.S. only) in wheel alignment Recommendations: Racking should have front and rear jacking capability. Equipment Maintenance and Calibration: Alignment machines must be regularly calibrated in order to give correct information. Most manufacturers recommend the following: - Alignment machines with "internal reference" sensors should be checked (and calibrated, if necessary) every six months. - Alignment machines with "external reference" (image-based camera technology) should be checked (and calibrated, if necessary) once a year. - Racks must be kept level to within 1.6 mm (1/16 in). - If any instrument that is part of the alignment machine is dropped or damaged in some way, check the calibration immediately. Check with the manufacturer of your specific equipment for their recommended service/calibration schedule. Wheel Alignment Process When performing wheel alignment measurement and/or adjustment, the following steps should be taken: Preliminary Steps: 1. Verify that the vehicle has a full tank of fuel (compensate as necessary). 2. Inspect the wheels and the tires for damage. 3. Inspect the tires for the proper inflation and irregular tire wear. 4. Inspect the wheel bearings for excessive play. 5. Inspect all suspension and steering parts for looseness, wear, or damage. 6. Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components. 7. Inspect the vehicle trim height. 8. Compensate for frame angle on targeted vehicles (refer to Wheel Alignment Specifications in SI). Satisfactory vehicle operation may occur over a wide range of alignment angles. However, if the wheel alignment angles are not within the range of specifications, adjust the wheel alignment to the specifications. Refer to Wheel Alignment Specifications in SI. Give consideration to excess loads, such as tool boxes, sample cases, etc. Follow the wheel alignment equipment manufacturer's instructions. Measure/Adjust: Important Prior to making any adjustments to wheel alignment on a vehicle, technicians must verify that the wheel alignment specifications loaded into their wheel alignment machine are up-to-date by comparing these to the wheel alignment specifications for the appropriate model and model year in SI. Using incorrect and/or outdated specifications may result in unnecessary adjustments, irregular and/or premature tire wear and repeat customer concerns Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1483 Important When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front wheel alignment angles. Perform the following steps in order to measure the front and rear alignment angles: 1. Install the alignment equipment according to the manufacturer's instructions. 2. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment. 3. Measure the alignment angles and record the readings. If necessary, adjust the wheel alignment to vehicle specification and record the before and after measurements. Refer to Wheel Alignment Specifications in SI. Important Technicians must refer to SI for the correct wheel alignment specifications. SI is the only source of GM wheel alignment specifications that is kept up-to-date throughout the year. Test drive vehicle to ensure proper repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1484 Frame Angle Measurement (Express / Savana Only) ........ Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1485 What corrected the customer concern and was the repair verified? Please Explain: ............. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening Alignment: All Technical Service Bulletins Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Important: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 1490 Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 1491 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications Alignment: All Technical Service Bulletins Steering/Suspension - Wheel Alignment Specifications WARRANTY ADMINISTRATION Bulletin No.: 05-03-07-009C Date: December 09, 2010 Subject: Wheel Alignment Specifications, Requirements and Recommendations for GM Vehicles Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks Supercede: This bulletin is being extensively revised to provide technicians and warranty administrators with an all inclusive guide for wheel alignments. PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. Please discard Corporate Bulletin Number 05-03-07-009B (Section 03 - Suspension). Purpose The purpose of this bulletin is to provide retail, wholesale and fleet personnel with General Motors' warranty service requirements and recommendations for customer concerns related to wheel alignment. For your convenience, this bulletin updates and centralizes all of GM's Standard Wheel Alignment Service Procedures, Policy Guidelines and bulletins on wheel alignment warranty service. Important PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. The following five (5) key steps are a summary of this bulletin and are REQUIRED in completing a successful wheel alignment service. 1. Verify the vehicle is in an Original Equipment condition for curb weight, tires, wheels, suspension and steering configurations. Vehicles modified in any of these areas are not covered for wheel alignment warranty. 2. Review the customer concern relative to "Normal Operation" definitions. 3. Verify that vehicle is within the "Mileage Policy" range. 4. Document wheel alignment warranty claims appropriately for labor operations E2000 and E2020. The following information must be documented or attached to the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 5. Use the proper wheel alignment equipment (preferred with print-out capability), process and the appropriate calibration maintenance schedules. Important If it is determined that a wheel alignment is necessary under warranty, use the proper labor code for the repair. E2000 for Steering Wheel Angle and/or Front Toe set or E2020 for Wheel Alignment Check/Adjust includes Caster, Camber and Toe set (Wheel alignment labor time for other component repairs is to be charged to the component that causes a wheel alignment operation.). The following flowchart is to help summarize the information detailed in this bulletin and should be used whenever a wheel alignment is performed. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1497 Verify Original Equipment Condition of the Vehicle - Verify that Original Equipment Tires and Wheels or Official GM Accessory Tires and Wheels are on the vehicle. - Verify that aftermarket suspension "Lift" or "Lowering" Kits or other suspension alterations have NOT been done to the vehicle. - Check for accidental damage to the vehicle; for example, severe pothole or curb impacts, collision damage that may have affected the wheel alignment of the vehicle; e.g., engine cradles, suspension control arms, axles, wheels, wheel covers, tires may show evidence of damage/impact. - Check to be sure vehicle has seen "Normal Use" rather than abuse; e.g., very aggressive driving may show up by looking at the tires and condition of the vehicle. - Check for other additional equipment items that may significantly affect vehicle mass such as large tool boxes, campers, snow plow packages (without the snowplow RPO), etc., especially in trucks and cutaway/incomplete vehicles. Significant additional mass can affect trim height and wheel alignment of the vehicle and may necessitate a customer pay wheel alignment when placed semi-permanently in the vehicle (Upfitter instructions are to realign the vehicle after placement of these types of items. (This typically applies to trucks and incomplete vehicles that can be upfit with equipment such as the above.) Customer Concerns, "Normal Operation" Conditions and "Mileage Policy" Possible Concerns The following are typical conditions that may require wheel alignment warranty service: 1. Lead/Pull: defined as "at a constant highway speed on a typical straight road, the amount of effort required at the steering wheel to maintain the vehicle's straight heading." Important Please evaluate for the condition with hands-on the steering wheel. Follow the "Vehicle Leads/Pulls" diagnostic tree located in SI to determine the cause of a lead/pull concern. Lead/Pull concerns can be due to road crown or road slope, tires, wheel alignment or even in rare circumstances a steering gear issue. Lead/pull concerns due to road crown are considered "Normal Operation" and are NOT a warrantable condition -- the customer should be advised that this is "Normal Operation." Important Some customers may comment on a "Lead/Pull" when they hold the steering wheel in a level condition. If so, this is more likely a "steering wheel angle" concern because the customer is "steering" the vehicle to obtain a "level" steering wheel. 2. Steering wheel angle to the left or right (counter-clockwise or clockwise, respectively): Defined as the steering wheel angle (clocking) deviation from "level" while maintaining a straight heading on a typical straight road. 3. Irregular or Premature tire wear: Slight to very slight "feathering" or "edge" wear on the shoulders of tires is NOT considered unusual and should even out with a tire rotation; if the customer is concerned about a "feathering" condition of the tires, the customer could be advised to rotate the tires earlier than the next scheduled mileage/maintenance interval (but no later than the next interval). Be sure to understand the customer's driving habits as this will also heavily influence the tire wear performance; tire wear from aggressive or abusive driving habits is NOT a warrantable condition. Important Slight or mild feathering, cupping, edge or heel/toe wear of tire tread shoulders is "normal" and can show up very early in a tire/vehicle service mileage; in fact, some new tires can show evidence of feathering from the factory. These issues do NOT affect the overall performance and tread life of the tire. Dealer personnel should always check the customer's maintenance records to ensure that tire inflation pressure is being maintained to placard and that the tires are being rotated (modified-X pattern) at the proper mileage intervals. Wheel alignments are NOT to be performed for the types of "Normal" Tire Feathering shown in Figures 1-4 below. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1498 Figure 1: Full Tread View - "NORMAL" Tire "Feathering" Wear on the Shoulder/Adjacent/Center Ribs Figure 2: Tire Shoulder View Example 1 - "NORMAL" Tire "Feathering" Wear on the Shoulder Figure 3: Tire Shoulder View Example 2 - "NORMAL" Tire "Feathering" Wear Figure 4: Detail Side View of Tire Shoulder Area - "NORMAL" Tire "Feathering" Wear Important When a wheel alignment is deemed necessary for tire wear, be sure to document on the repair order, in as much detail as possible, the severity and type of tire wear (e.g., severe center wear or severe inside or outside shoulder wear) and the position of the tire on the vehicle (RF, LF, LR, RR). Please note the customer's concern with the wear such as, noise, appearance, wear life, etc. A field product report with pictures of the tire wear condition is recommended. Refer to Corporate Bulletin Number 02-00-89-002J and #07-00-89-036C. 4. Other repairs that affect wheel alignment; e.g., certain component replacement such as suspension control arm replacement, engine cradle adjustment/replace, steering gear replacement, steering tie rod replace, suspension strut/shock, steering knuckle, etc. may require a wheel alignment. Important If other components or repairs are identified as affecting the wheel alignment, policy calls for the wheel alignment labor time to be charged to the replaced/repaired component's labor operation time rather than the wheel alignment labor operations. Important Vibration type customer concerns are generally NOT due to wheel alignment except in the rare cases; e.g., extreme diagonal wear across the tread. In general, wheel alignments are NOT to be performed as an investigation/correction for vibration concerns. "Normal Operation" Conditions Vehicle Lead/Pull Due to Road Crown or Slope: As part of "Normal Operation," vehicles will follow side-to-side or left to right road crown or slope. Be sure to verify from the customer the types of roads they are driving as they may not recognize the influence of road crown on vehicle lead/pull and steering wheel angle. If a vehicle requires significant steering effort to prevent it from "climbing" the road crown there may be an issue to be looked into further. Important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1499 A wheel alignment will generally NOT correct vehicles that follow the road crown since this is within "Normal Operation." Mileage Policy The following mileage policy applies for E2020 and E2000 labor operations: Note Wheel Alignment is NOT covered under the New Vehicle Limited Warranty for Express and Savana Cutaway vehicles as these vehicles require Upfitters to set the wheel alignment after completing the vehicles. - 0-800 km (0-500 mi): E2000/E2020 claims ONLY allowed with Call Center Authorization. Due to the tie down during shipping, the vehicle's suspension requires some time to reach normal operating position. For this reason, new vehicles are generally NOT to be aligned until they have accumulated at least 800 km (500 mi). A field product report should accompany any claim within this mileage range. - 801-12,000 km (501-7,500 mi): - If a vehicle came from the factory with incorrect alignment settings, any resulting off-angle steering wheel, lead/pull characteristics or the rare occurrence of excessive tire wear would be apparent early in the life of the vehicle. The following policy applies: - Vehicles 100% Factory Set/Measured for Caster/Camber/Toe - Escalade/ESV/EXT, Tahoe/Suburban, Yukon/XL/Denali, Silverado/Sierra, Express/Savana, Corvette and Colorado/Canyon: E2000/E2020 Claims: Call Center Authorization Required - All Vehicles NOT 100% Factory Set/Measured for Caster/Camber/Toe as noted above: E2000/E2020 Claims: Dealer Service Manager Authorization Required - 12,001 km and beyond (7,501 miles and beyond): During this period, customers are responsible for the wheel alignment expense or dealers may provide on a case-by case basis a one-time customer enthusiasm claim up to 16,000 km (10,000 mi). In the event that a defective component required the use of the subject labor operations, the identified defective component labor operation will include the appropriate labor time for a wheel alignment as an add condition to the component repair. Important Only one wheel alignment labor operation claim (E2000 or E2020) may be used per VIN. Warranty Documentation Requirements When a wheel alignment service has been deemed necessary, the following items will need to be clearly documented on/with the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 1. Document the customer concern in as much detail as possible on the repair order and in the warranty administration system. Preferred examples: - Steering wheel is off angle in the counterclockwise direction by approximately x degrees or clocking position. - Vehicle lead/pulls to the right at approximately x-y mph. Vehicle will climb the road crown. Severe, Moderate or Slight. - RF and LF tires are wearing on the outside shoulders with severe feathering. Important In the event of a lead/pull or steering wheel angle concern, please note the direction of lead/pull (left or right) or direction of steering wheel angle (clockwise or counterclockwise) on the repair order and within the warranty claim verbatim. Important In the event of a tire wear concern, please note the position on the vehicle and where the wear is occurring on the tire; i.e., the RF tire is wearing on the inside shoulder. 2. Document the technician's findings on cause and correction of the issue. Examples: - Reset LF toe from 0.45 degrees to 0.10 degrees and RF toe from -0.25 degrees to 0.10 degrees to correct the steering wheel angle from 5 degrees counterclockwise to 0 degrees. - Reset LF camber from 0.25 degrees to -0.05 degrees to correct the cross-camber condition of +0.30 degrees to 0.00 degrees on the vehicle. - Front Sum toe was found to be 0.50 degrees, reset to 0.20 degrees. 3. Print-out the "Before" and "After" wheel alignment measurements/settings and attach them to the Repair Order or if print-out capability is not Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1500 available, measurements may also be clearly and legibly handwritten into the Wheel Alignment Repair Order Questionnaire attached to this bulletin. 4. Attach the Wheel Alignment Repair Order Questionnaire below along with the print-out of "Before" and "After" wheel alignment measurements to the Repair Order and retain for use by GM. Wheel Alignment Equipment and Process Wheel alignments must be performed with a quality machine that will give accurate results when performing checks. "External Reference" (image-based camera technology) is preferred. Please refer to Corporate Bulletin Number 05-00-89-029B: General Motors Dealership Critical Equipment Requirements and Recommendations. Requirements: - Computerized four wheel alignment system. - Computer capable of printing before and after alignment reports. - Computer capable of time and date stamp printout. - Racking system must have jacking capability - Racking system must be capable of level to 1.6 mm (1/16 in) - Appropriate wheel stops and safety certification - Built-in turn plates and slip plates - Wheel clamps capable of attaching to 20" or larger wheels - Racking capable of accepting any GM passenger car or light duty truck - Operator properly trained and ASE-certified (U.S. only) in wheel alignment Recommendations: Racking should have front and rear jacking capability. Equipment Maintenance and Calibration: Alignment machines must be regularly calibrated in order to give correct information. Most manufacturers recommend the following: - Alignment machines with "internal reference" sensors should be checked (and calibrated, if necessary) every six months. - Alignment machines with "external reference" (image-based camera technology) should be checked (and calibrated, if necessary) once a year. - Racks must be kept level to within 1.6 mm (1/16 in). - If any instrument that is part of the alignment machine is dropped or damaged in some way, check the calibration immediately. Check with the manufacturer of your specific equipment for their recommended service/calibration schedule. Wheel Alignment Process When performing wheel alignment measurement and/or adjustment, the following steps should be taken: Preliminary Steps: 1. Verify that the vehicle has a full tank of fuel (compensate as necessary). 2. Inspect the wheels and the tires for damage. 3. Inspect the tires for the proper inflation and irregular tire wear. 4. Inspect the wheel bearings for excessive play. 5. Inspect all suspension and steering parts for looseness, wear, or damage. 6. Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components. 7. Inspect the vehicle trim height. 8. Compensate for frame angle on targeted vehicles (refer to Wheel Alignment Specifications in SI). Satisfactory vehicle operation may occur over a wide range of alignment angles. However, if the wheel alignment angles are not within the range of specifications, adjust the wheel alignment to the specifications. Refer to Wheel Alignment Specifications in SI. Give consideration to excess loads, such as tool boxes, sample cases, etc. Follow the wheel alignment equipment manufacturer's instructions. Measure/Adjust: Important Prior to making any adjustments to wheel alignment on a vehicle, technicians must verify that the wheel alignment specifications loaded into their wheel alignment machine are up-to-date by comparing these to the wheel alignment specifications for the appropriate model and model year in SI. Using incorrect and/or outdated specifications may result in unnecessary adjustments, irregular and/or premature tire wear and repeat customer concerns Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1501 Important When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front wheel alignment angles. Perform the following steps in order to measure the front and rear alignment angles: 1. Install the alignment equipment according to the manufacturer's instructions. 2. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment. 3. Measure the alignment angles and record the readings. If necessary, adjust the wheel alignment to vehicle specification and record the before and after measurements. Refer to Wheel Alignment Specifications in SI. Important Technicians must refer to SI for the correct wheel alignment specifications. SI is the only source of GM wheel alignment specifications that is kept up-to-date throughout the year. Test drive vehicle to ensure proper repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1502 Frame Angle Measurement (Express / Savana Only) ........ Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 1503 What corrected the customer concern and was the repair verified? Please Explain: ............. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 1504 Alignment: By Symptom Technical Service Bulletin # 533403 Date: 950501 Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 1505 Important: Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 1506 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 1507 Technical Service Bulletin # 533403 Date: 950501 Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 1508 Important: Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 1509 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Specifications > Vehicle Ride (Trim) Height Specifications Alignment: Specifications Vehicle Ride (Trim) Height Specifications Fig. 4 Vehicle Ride Height Measurement Locations & Specifications Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Specifications > Vehicle Ride (Trim) Height Specifications > Page 1512 Alignment: Specifications Alignment Specifications Front Alignment Specifications Caster Angle, Degrees Limits ................................................................................................................................................... ....................................................................... [01] Desired ................................................................. ....................................................................................................................................................... [03] Camber Angle, Degrees Limits ................................................................................................................................................... ................................................................ - 1 to +1 Desired ................................................................. ........................................................................................................................................................... 0 Total Toe, Degrees .............................................................................................................................. ............................................................... -.04 to +.36 Ball Joint Wear, Inch Lower Ball Stud [02] ............................................................................................................................ ..................................................................... .050 Upper Ball Stud [02] .............................................. ................................................................................................................................................... .125 [01] Left side, +2.25 to +4.25; right side, +2.75 to +4.75. [02] Refer to Suspension/Ball Joint, lower or Upper/Service and Repair for proper ball joint inspection procedure. [03] Left side, +3.25; right side, +3.75. Rear Alignment Specifications Thrust Angle, Degrees ......................................................................................................................... .............................................................. -.15 to +.15 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Service and Repair > Preliminary Inspection Alignment: Service and Repair Preliminary Inspection 1. Inspect tires for proper inflation and similar tread wear. 2. Inspect hub and bearing for excessive wear, repair as required. 3. Inspect ball joints. 4. Inspect tie rod ends for excessive looseness. 5. Check wheel and tire runout. 6. Inspect vehicle ride height. 7. Inspect rack and pinion for looseness at frame. 8. Ensure proper strut operation. 9. Check suspension and steering components for damage, replace as required. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Service and Repair > Preliminary Inspection > Page 1515 Alignment: Service and Repair Ride/Trim Height Measurement and Adjustment Fig. 4 Vehicle Ride Height Measurement Locations & Specifications Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Service and Repair > Preliminary Inspection > Page 1516 Alignment: Service and Repair Front Wheel Alignment Front Caster Adjustment Fig. 1 Caster & Camber Adjustments Caster adjustments are made by means of shims between the upper control arm inner support shaft and the support bracket attached to the frame, Fig. 1. Shims may be added, subtracted or transferred to change the readings. Transfer shims from front to rear or rear to front. The transfer of one shim to the front bolt from the rear bolt will decrease positive caster. One shim (1/32 inch) transferred from the rear bolt to the front bolt will change caster about 1/2 degree. Front Camber Adjustment Fig. 1 Caster & Camber Adjustments Camber adjustments are made by means of shims between the upper control arm inner support shaft and the support bracket attached to the frame, Fig. 1. Shims may be added, subtracted or transferred to change the readings. Change shims at both the front and rear of the shaft. Adding an equal number of shims at both front and rear of the support shaft will decrease positive camber. One shim (1/32 inch) at each location will move camber approximately 1/6 degree. Front Toe Adjustment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Alignment > System Information > Service and Repair > Preliminary Inspection > Page 1517 Fig. 2 Toe-in Adjustment Toe-in can be adjusted by loosening the clamp bolts at each end of each tie rod and turning each tie rod to increase or decrease its length as necessary until proper toe-in is secured and the steering gear is on the high point for straight-ahead driving, Fig. 2. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Fuel Pressure > Diagnostic Connector - Fuel Pump > Component Information > Locations Diagnostic Connector - Fuel Pump: Locations The fuel pump test connector is located in the engine compartment near the A/C accumulator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations Fuel Pressure Test Port Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations > Page 1526 Fuel Pressure Test Port: Service and Repair Fuel Test Port Valve CLEAN ^ Area around fuel pressure connection with GM X-3OA or equivalent. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery System / Service and Repair. 3. Fuel pressure connection valve assembly. INSTALL OR CONNECT 1. Fuel pressure connection valve assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ Turn ignition switch to the "ON" position for two seconds, then turn to the "OFF" position for ten seconds. Again turn to "ON" position, and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air/Fuel Mixture > System Information > Specifications Air/Fuel Mixture: Specifications The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air/Fuel Mixture > System Information > Specifications > Page 1530 Air/Fuel Mixture: Adjustments The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Idle Speed > System Information > Specifications Idle Speed: Specifications The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Idle Speed > System Information > Specifications > Page 1534 Idle Speed: Adjustments The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Cleaner Fresh Air Duct/Hose > Component Information > Locations Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: Customer Interest Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 1547 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: All Technical Service Bulletins Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 1553 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 1554 Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 1555 Air Filter Element: Service and Repair Air Ducting Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 1556 REMOVE OR DISCONNECT 1. Loosen wing nuts at front of air cleaner housing. 2. Lift air cleaner lid, Mass Air Flow (MAF) sensor and resonator as a unit. 3. Remove air filter element. INSTALL OR CONNECT 1. Install air filter element. 2. Move air cleaner lid, MAF sensor and resonator into place. 3. Tighten wing nuts. 4. Check clamps at MAF sensor and tighten if necessary. 5. Check joints between duct, resonators and throttle body for possible air leaks. Repair if necessary. NOTICE: If the Mass Air Flow (MAF) sensor is installed backwards, the system will go rich. An arrow cast into the plastic portion of the sensor indicates proper air flow direction. The arrow must point toward the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Fuel Filter > Fuel Pressure Release > System Information > Service and Repair Fuel Pressure Release: Service and Repair WARNING: - To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing fuel system components. - After relieving the fuel system pressure a small amount of fuel may be released when servicing fuel lines or connections. In order to reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting, to catch any fuel that may leak out. Place the shop towel in an approved container when the disconnect is complete. Fuel Pressure Test Port PROCEDURE: 1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine. 2. Loosen the fuel filler cap to relieve tank pressure. 3. Connect the J 34730-1 fuel pressure gauge to the fuel pressure connection on the fuel rail. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage. 4. Install a bleed hose into an approved container and open the valve slowly to relieve system pressure. Fuel connections are now safe for servicing. 5. Drain any fuel remaining in the gauge into an approved container. NOTE: After repairs are complete, tighten the fuel cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Firing Order > Component Information > Specifications > Ignition Firing Order Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Ignition Timing > Number One Cylinder > Component Information > Locations > Number 1 Cylinder Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation Timing Marks and Indicators: Locations Crankshaft Rotation Crankshaft Rotation (Typical Crankshaft Pulley) Crankshaft rotation is clockwise when viewed from in front of the crankshaft pulley as shown in the generic image. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation > Page 1574 Timing Marks and Indicators: Locations Timing Marks The ignition timing is completely controlled by the Powertrain Control Module (PCM). No timing reference marks are provided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications Spark Plug Wire: Specifications Wire Harness Support Bolt / Screw ............................................................................................................................................................ 40 Nm (30 lb ft.) Wire Harness Support Channel Bolt / Screw (Right) ................................................................................................................................ 12 Nm (106 lb in.) Wire Harness Support Channel Bolt/Screw (Left) ..................................................................................................................................... 12 Nm (106 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1578 Spark Plug Wire: Locations Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1579 Spark Plug Harness Routing The spark plug wires run down both sides of the engine block under the exhaust manifolds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1580 Spark Plug Wire: Description and Operation The spark plug wire hamess assemblies use carbon impregnated cord conductors, encased in 8 mm (5 / 16-inch) diameter silicone jackets. The silicone jackets withstand very high temperatures and also provide excellent insulation for the high voltage of the system. Silicone spark plug boots form a tight seal to the spark plugs. The material used to construct spark plug wires is very soft. This wire will withstand more heat and carry a higher voltage, but chaffing and cutting become easier. The spark plug wires must be routed correctly to prevent chafing or cutting. When removing a spark plug wire from a spark plug, twist the boot on the spark plug one-half turn while pulling on the boot. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1581 Spark Plug Wire: Testing and Inspection Inspect spark plug wires visually first for any cuts, burns, or damage. While engine is running, inspect for any arcing to ground or other components. Use a spray bottle to lightly coat the spark plug wires with water while observing idle quality. If idle quality diminishes or engine stalls, spark plug wires should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1582 Spark Plug Wire: Service and Repair Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1583 Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1584 Spark Plug Harness Routing NOTICE: The boots should be twisted one-half turn while removing. Do not pull on the wire harnesses to remove them from the spark plugs. Pull on the boots, or use a tool designed for this purpose. REMOVE OR DISCONNECT Numbers included in this procedure refer to caption numbers in the included images. 1. Left bank spark plug wire boots from spark plugs. 2. Left bank spark plug wire harness support channel bolts / screws (19) and channel. Rear bolt / screw (19) is located behind exhaust manifold takedown. Loosen this bolt / screw using a 10 mm wrench then slide channel upward to disengage from bolt / screw (19). 3. Left bank spark plug wire harness from clip (17) located behind air injection reactor (AIR) pump. 4. Right bank spark plug wire boots from spark plugs. 5. Air intake resonator. With mechanical cooling fan: A. Upper radiator fan shroud, B. Loosen fan pulley nuts. C. Fan belt. D. Mechanical fan and pulley. E. Mechanical fan pulley bracket nuts and bracket. F. Radiator outlet pipe nuts from A/C compressor mounting studs. 6. Serpentine drive belt. 7. Raise and suitably support vehicle. 8. Transmission oil cooler line support bolt / screw from accessory drive bracket. 9. Serpentine drive belt tensioner bolts/screws and tensioner. 10. A/C compressor attaching bolts/screws Reposition A/C compressor to provide access to front wire harness support (27). 11. Right wire harness support bolt / screw (28). 12. Right wire harness from support (27). 13. Left and right bank spark plug wire harnesses (6) from distributor. 14. Left wire harness from clips (17, 20, 21 and 23). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 1585 ^ Insert screwdriver into tab on top of clip to disengage. 15. Right wire harness from clips (16, 17, and 21). ^ Insert screwdriver into tab on top of clip to disengage. NOTICE: When replacing spark plug wire harnesses (secondary wiring), route the wire harnesses correctly and through the proper retainers. Failure to route the wire harnesses properly can lead to radio ignition noise and cross-firing of the spark plugs, or shorting of the leads to ground. INSTALL OR CONNECT 1. Right wire harness to clips (16, 17 and 21). 2. Left wire harness to clips (17, 20, 21 and 23). 3. Right wire harness to support (27). 4. Right wire harness support bolt / screw (28). Tighten ^ Bolt / screw (28) to 40 Nm (30 lb ft.). 5. A/C compressor to bracket. 6. A/C compressor attaching bolts / screws and rear bracket nut. Tighten A. A/C compressor bolts / screws to 50 Nm (37 lb ft.). B. A/C compressor rear bracket nut to 41 Nm (30 lb ft.). 7. Serpentine drive belt tensioner and tensioner bolts / screws. Tighten ^ Tensioner bolts / screws to 25 Nm (18 lb ft.). 8. Transmission oil cooler line support bolt / screw. Tighten ^ Oil cooler line support bolt / screw to 1.9 Nm (17 lb in.). 9. Lower vehicle. 10. Serpentine drive belt. With mechanical cooling fan: A. Radiator outlet pipe nuts from A/C compressor mounting studs. Tighten ^ Radiator outlet pipe nuts to 16 Nm (12 lb ft.). B. Mechanical fan pulley bracket nuts and bracket. Tighten ^ Mechanical fan pulley bracket nuts to 50 Nm (37 lb .ft). C. Mechanical fan pulley, fan and nuts. ^ Finger tighten only. D. Fan belt. Tighten ^ Mechanical fan nuts to 26 Nm (19 lb ft.). E. Upper radiator fan shroud. 11. Air intake resonator. 12. Right bank spark plug wire boots to spark plugs. 13. Left bank spark plug wire harness to clip (17) located behind AIR pump. 14. Left bank spark plug wire harness support channel and bolts/screws (19). Rear bolt / screw (19) is located behind exhaust manifold takedown. Slide channel onto bolt / screw (19) then tighten using a 10 mm wrench. 15. Left bank spark plug wire harness boots to spark plugs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Specifications Distributor Cap: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement Distributor Cap: Service and Repair Replacement Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Distributor cap (30). 2. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 3. Vacuum harness assembly to distributor assembly. 4. Connect four-terminal PCM connector to distributor. 5. Spark plug wire harness assemblies to distributor assembly. 6. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement > Page 1592 Distributor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications Ignition Rotor: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Distributor Rotor Bolt / Screw .............................................................................................................. ....................................................... 0.7 Nm (6 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 1596 Ignition Rotor: Service and Repair Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). 7. Rotor bolts / screws (32) using J 39998 or equivalent. 8. Rotor assembly (32). 9. Distributor cover (33) and shield (34). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Shield (34) and distributor cover (33). 2. Rotor (32). 3. Rotor bolts / screws (31) using J 39998 or equivalent. Tighten ^ Rotor bolts / screws (31) to 0.7 Nm (61 lb in.). 4. Distributor cap (30). 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 1597 ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 6. Vacuum harness assembly to distributor assembly. 7. Connect four-terminal PCM connector to distributor. 8. Spark plug wire harness assemblies to distributor assembly. 9. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications Spark Plug: Specifications Spark Plug Install Torque .................................................................................................................... ........................................................ 27 Nm (20 lb ft.) Spark Plug Gap ................................................................................................................................... ........................................................ 1.27 mm (0.050") Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 1601 Spark Plug Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 1602 Spark Plug: Service Precautions It is important that technicians wash their hands after handling coated spark plugs and before smoking. The coating itself is a nonhazardous material and incidental contact will not cause any adverse affects. However, exposure to polymer vapors (the result of a cigarette being coated from handling, then burned) may cause flu like symptoms and should be avoided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 1603 Spark Plug ID Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 1604 Spark Plug: Description and Operation Platinum-tipped, resistor-type, tapered-seat spark plugs are used on the engine assembly. No gasket is used on these tapered-seat spark plugs. When replacing spark plugs, use only the type specified. Normal service is assumed to be a mixture of idling, slow speed, and high speed driving. Occasional or intermittent high-speed driving is needed for good spark plug performance. It gives increased combustion heat, burning away carbon or oxides that have built up from frequent idling, or continual stop-and-go driving. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 1605 Spark Plug: Testing and Inspection WORN OR DIRTY Worn or dirty spark plugs may give satisfactory operation at idling speed, but frequently fail at higher rpm. Faulty spark plugs may cause poor fuel economy, power loss, loss of speed, hard starting and generally poor engine performance. Follow the scheduled maintenance service recommendations to assure satisfactory spark plug performance. NORMAL Normal spark plug operation will result in brown to grayish - tan deposits appearing on the portion of the spark plug that projects into the cylinder area. A small amount of red - brown, yellow, and white powdery material may also be present on the insulator tip around the center electrode. These deposits are normal combustion by-products of fuels and lubricating oils with additives. MISFIRING Engine assemblies which are not running properly are often referred to as "misfiring." This means the ignition spark is not igniting the fuel/air mixture at the proper time, While other ignition and fuel system causes must also be considered, possible causes include ignition system conditions which allow the spark voltage to reach ground in some other manner than by jumping across the air gap at the tip of the spark plug, leaving the fuel/air mixture unburned. Misfiring may also occur when the tip of the spark plug becomes overheated and ignites the mixture before the spark jumps. This is referred to as "pre-ignition." CARBON FOULING Carbon fouling of the spark plug is indicated by dry, black carbon (soot) deposits on the portion of the spark plug in the cylinder. Excessive idling and slow speeds under light engine loads can keep the spark plug temperatures so low that these deposits are not burned off. Over - rich fuel mixtures or poor ignition system output may also be the cause. OIL FOULING Oil fouling of the spark plug is indicated by wet oily deposits on the portion of the spark plug in the cylinder. This may be caused by oil getting past worn piston rings. This condition also may occur during break-in of new or newly overhauled engine assemblies. DEPOSITS Deposit fouling of the spark plug occurs when the normal red - brown, yellow or white deposits of combustion by - products become sufficient to cause misfiring. In some cases, these deposits may melt and form a shiny glaze on the insulator around the center electrode. If the fouling is found in only one or two cylinders, valve stem clearances or intake valve seals may be allowing excess lubricating oil to enter the cylinder, particularly if the deposits are heavier on the side of the spark plug that was facing the intake valve. CRACKED OR BROKEN Cracked or broken insulators may be the result of improper installation or heat shock to the insulator material. Upper insulators can be broken when a poorly fitting tool is used during installation or removal, or when the park plug is hit from the outside. Cracks in the upper insulator may be inside the shell and not visible. Also, the breakage may not cause problems until oil or moisture penetrates the crack later. A broken or cracked lower insulator tip (around the center electrode) may result from "heat shock" (spark plug suddenly operating too hot). "Heat shock" breakage in the lower insulator tip generally occurs during severe engine operating conditions (high speeds or heavy loading) and may be caused by over - advanced timing or low grade fuels. Heat shock refers to a rapid increase in the tip temperature that causes the insulator material to crack. Damage during gapping can happen if the gapping tool is pushed against the center electrode or the insulator around it, causing the insulator to crack. When gapping a spark plug, make the adjustment by only bending the ground side terminal, keeping the tool clear of other parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 1606 Spark Plug: Service and Repair Spark Plug Assembly REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Spark plug wire harness assemblies from spark plugs. Refer to "Spark Plug Wire Harness Assembly Replacement" in this section. ^ Note positions of wires before removing. NOTICE: Clean dirt and debris from spark plug recess areas. 3. Spark plugs from cylinder head assemblies. NOTICE: Be sure spark plugs thread smoothly into cylinder head assemblies and are fully seated. Cross threading or failing to fully seat spark plugs can cause overheating of spark plugs, exhaust blow-by, or thread damage. Follow recommended torque specifications carefully. Over or under - tightening can also cause severe damage to cylinder head assemblies or spark plug. Check spark plug gap using a wire type gauge before installing. If spark plug gaps are not adjusted correctly, engine idle quality may be seriously affected. A wire type gauge must be used (as opposed to a flat feeler type gauge) to insure an accurate reading. INSTALL OR CONNECT 1. Spark plugs to cylinder head assemblies. Tighten ^ Spark plugs to 27 Nm (20 lb ft.). 2. Spark plug wire harness assemblies, routed properly as note during removal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Compression Check > System Information > Specifications Compression Check: Specifications The lowest reading cylinder should not be less than 70% of the highest and no cylinder reading should be less than 689 kPa (100 psi). Perform compression test with engine at normal operating temperature, spark plugs removed and throttle wide open. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Valve Clearance > System Information > Specifications Valve Clearance: Specifications VALVE LASH Turn rocker arm stud nut until all lash is eliminated (zero lash), then tighten nut additional turn in 1/4 turn increments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Tune-up and Engine Performance Checks > Valve Clearance > System Information > Specifications > Page 1613 Valve Clearance: Adjustments Fig. 5 Valve Lash Adjustment Adjust valves, Fig.5, with engine at normal operating temperature. Rotate engine until No. 1 cylinder is in position to fire. Adjust exhaust valves 1-3-4-8 and intake valves 1-2-5-7. Crank engine one complete revolution, then adjust exhaust valves 2-5-6-7 and intake vales 3-4-6-8. On all engines, the following procedure, performed with the engine running, should only be performed if readjustment is required. 1. After engine has been warmed up to normal operating temperature, remove valve cover and install a new valve cover gasket. 2. With engine running at idle speed, back off valve rocker arm nut until rocker arm starts to clatter. 3. Turn rocker arm nut down slowly until clatter just stops. This is the zero lash position. 4. Turn nut down 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat additional 1/4 turns, pausing 10 seconds each time, until nut has been turned down the number of turns listed in "Valve Clearance Specifications chart from the zero lash position. This preload adjustment must be done slowly to allow lifter to adjust itself to prevent the possibility of interference between valve head and top of piston, which might result in internal damage and/or bent push rods. Noisy lifters should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics Drive Belt: Technical Service Bulletins Engine - Drive Belt Misalignment Diagnostics INFORMATION Bulletin No.: 08-06-01-008A Date: July 27, 2009 Subject: Diagnosing Accessory Drive Belt / Serpentine Belt Noise and Availability and Use of Kent-Moore EN-49228 Laser Alignment Tool - Drive Belt Models: 2010 and Prior GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 Vehicles 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add a model year and update the Tool Information. Please discard Corporate Bulletin Number 08-06-01-008 (Section 06 - Engine). Background Several aftermarket companies offer laser alignment tools for accessory drive systems that can be very helpful in eliminating drive belt noise as a result of misaligned pulleys. Typically pricing ranges from $160 - $200. EN-49228 Laser Alignment Tool - Drive Belt The GM Tool program has now made available a competitive, simple to use and time-saving laser tool to assist in achieving precise alignment of the drive belt pulleys. This optional tool removes the guesswork from proper pulley alignment and may serve to reduce comebacks from: - Drive Belt Noise - Accelerated Drive Belt Wear - Drive Belt Slippage Instructions The instructions below are specific only to the truck Gen IV V-8 family of engines. These instructions are only for illustrative purposes to show how the tool may be used. Universal instructions are included in the box with the Laser Alignment Tool - Drive Belt. Caution - Do not look directly into the beam projected from the laser. - Use caution when shining the laser on highly polished or reflective surfaces. Laser safety glasses help reduce laser beam glare in many circumstances. - Always use laser safety glasses when using the laser. Laser safety glasses are not designed to protect eyes from direct laser exposure. 1. Observe and mark the serpentine belt orientation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics > Page 1618 2. Remove the serpentine belt from the accessory drive system. 3. Install the tool onto the power steering pulley. Position the legs of the tool into the outer grooves of the pulley, farthest from the front of the engine. 4. Install the retaining cord around the pulley and to the legs of the tool. 5. Put on the laser safety glasses provided with the tool. 6. Depress the switch on the rear of the tool to activate the light beam. 7. Rotate the power steering pulley as required to project the light beam onto the crankshaft balancer pulley grooves. 8. Inspect for proper power steering pulley alignment. - If the laser beam projects onto the second rib or raised area (1), the pulleys are aligned properly. - If the laser beam projects more than one-quarter rib 0.9 mm (0.035 in) mis-alignment, adjust the position of the power steering pulley as required. - Refer to SI for Power Steering Pulley Removal and Installation procedures. 9. Install the serpentine belt to the accessory drive system in the original orientation. 10. Operate the vehicle and verify that the belt noise concern is no longer present. Tool Information Please visit the GM service tool website for pricing information or to place your order for this tool. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics > Page 1619 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics > Page 1620 Drive Belt: Technical Service Bulletins Engine - Serpentine Drive Belt Wear Information Bulletin No.: 04-06-01-013 Date: April 29, 2004 INFORMATION Subject: Information on Serpentine Belt Wear Models: 2004 and Prior Passenger Cars and Trucks 2003-2004 and Prior HUMMER H2 All current GM vehicles designed and manufactured in North America were assembled with serpentine belts that are made with an EPDM material and should last the life of the vehicle. It is extremely rare to observe any cracks in EPDM belts and it is not expected that they will require maintenance before 10 years or 240,000 km (150,000 mi) of use. Older style belts, which were manufactured with a chloroprene compound, may exhibit cracks depending on age. However, the onset of cracking typically signals that the belt is only about halfway through its usable life. A good rule of thumb for chloroprene-based belts is that if cracks are observed 3 mm (1/8 in) apart, ALL AROUND THE BELT, the belt may be reaching the end of its serviceable life and should be considered a candidate for changing. Small cracks spaced at greater intervals should not be considered as indicative that the belt needs changing. Any belt that exhibits chunking should be replaced. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Drive Belt > Component Information > Specifications > Serpentine Belt Tension Specification Drive Belt: Specifications Serpentine Belt Tension Specification Engines equipped with serpentine belts have an automatic tensioner. No adjustment of this is necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Drive Belt > Component Information > Specifications > Serpentine Belt Tension Specification > Page 1623 Drive Belt: Specifications Air Conditioning Belt Tension Specification New ..................................................................................................................................................... ............................................................... 105-125 Lbs Used .................................................................................................................................................... ............................................................... 105-125 Lbs Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Drive Belt > Component Information > Specifications > Page 1624 Drive Belt: Service and Repair Fig. 16 Serpentine Drive Belt Routing SERPENTINE DRIVE BELT BELT ROUTING Refer to Fig.16. for serpentine belt routing diagrams. BELT REPLACEMENT 1. Disconnect battery ground cable. 2. On models with mechanical cooling fan, proceed as follows: a. Rotate mechanical cooling fan tensioner pulley clockwise using a suitable 13 mm wrench while sliding belt from tensioner pulley. b. Remove fan belt from pulleys. c. Remove radiator outlet nuts at air conditioning compressor. 3. On all models, rotate tensioner pulley clockwise using a suitable 9/16 offset wrench while sliding belt from tensioner, then remove serpentine drive belt. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Cleaner Fresh Air Duct/Hose > Component Information > Locations Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T Shift/Driveability Concerns/MIL ON Air Filter Element: Customer Interest Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T Shift/Driveability Concerns/MIL ON > Page 1638 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: All Technical Service Bulletins Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 1644 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 1645 Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 1646 Air Filter Element: Service and Repair Air Ducting Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 1647 REMOVE OR DISCONNECT 1. Loosen wing nuts at front of air cleaner housing. 2. Lift air cleaner lid, Mass Air Flow (MAF) sensor and resonator as a unit. 3. Remove air filter element. INSTALL OR CONNECT 1. Install air filter element. 2. Move air cleaner lid, MAF sensor and resonator into place. 3. Tighten wing nuts. 4. Check clamps at MAF sensor and tighten if necessary. 5. Check joints between duct, resonators and throttle body for possible air leaks. Repair if necessary. NOTICE: If the Mass Air Flow (MAF) sensor is installed backwards, the system will go rich. An arrow cast into the plastic portion of the sensor indicates proper air flow direction. The arrow must point toward the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Cabin Air Filter > Component Information > Locations Cabin Air Filter: Locations This vehicle does not contain a factory installed cabin air filter. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Fuel Filter > Fuel Pressure Release > System Information > Service and Repair Fuel Pressure Release: Service and Repair WARNING: - To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing fuel system components. - After relieving the fuel system pressure a small amount of fuel may be released when servicing fuel lines or connections. In order to reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting, to catch any fuel that may leak out. Place the shop towel in an approved container when the disconnect is complete. Fuel Pressure Test Port PROCEDURE: 1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine. 2. Loosen the fuel filler cap to relieve tank pressure. 3. Connect the J 34730-1 fuel pressure gauge to the fuel pressure connection on the fuel rail. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage. 4. Install a bleed hose into an approved container and open the valve slowly to relieve system pressure. Fuel connections are now safe for servicing. 5. Drain any fuel remaining in the gauge into an approved container. NOTE: After repairs are complete, tighten the fuel cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Filters > Oil Filter, Engine > Component Information > Technical Service Bulletins > Engine - Noise/Damage Oil Filter Application Importance Oil Filter: Technical Service Bulletins Engine - Noise/Damage Oil Filter Application Importance INFORMATION Bulletin No.: 07-06-01-016B Date: July 27, 2009 Subject: Information on Internal Engine Noise or Damage After Oil Filter Replacement Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being updated to add model years. Please discard Corporate Bulletin Number 07-06-01-016A (Section 06 - Engine/Propulsion System). Important Engine damage that is the result of an incorrect or improperly installed engine oil filter is not a warrantable claim. The best way to avoid oil filter quality concerns is to purchase ACDelco(R) oil filters directly from GMSPO. Oil filter misapplication may cause abnormal engine noise or internal damage. Always utilize the most recent parts information to ensure the correct part number filter is installed when replacing oil filters. Do not rely on physical dimensions alone. Counterfeit copies of name brand parts have been discovered in some aftermarket parts systems. Always ensure the parts you install are from a trusted source. Improper oil filter installation may result in catastrophic engine damage. Refer to the appropriate Service Information (SI) installation instructions when replacing any oil filter and pay particular attention to procedures for proper cartridge filter element alignment. If the diagnostics in SI (Engine Mechanical) lead to the oil filter as the cause of the internal engine noise or damage, dealers should submit a field product report. Refer to Corporate Bulletin Number 02-00-89-002I (Information for Dealers on How to Submit a Field Product Report). Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Hoses > System Information > Service Precautions Hoses: Service Precautions SERVICE PRECAUTIONS To prevent vehicle damage, always observe the following precautions: After servicing a hose, check for leaks before and after test driving the vehicle. - Always use the correct size hose. Do not use standard sized hose in place of metric hose or vice versa. Always use the correct type of hose. Never use vacuum hose in place of fuel hose. Never use heater hose in place of PCV hose. - When replacing hoses which are attached to the engine on one end and the frame or body on the other end, always leave sufficient length to compensate for engine movement (from torque). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Brake Fluid > Component Information > Technical Service Bulletins > Brake Fluid - Level & Filling Recommendations Brake Fluid: Technical Service Bulletins Brake Fluid - Level & Filling Recommendations File In Section: 05 - Brakes Bulletin No.: 00-05-22-004 Date: May, 2000 INFORMATION Subject: Brake Fluid Level and Filling Recommendations Models: 2001 and Prior Passenger Cars and Trucks Many dealers and after-market repair shops advertise multi-point fluid "top-ups" in conjunction with oil changes or regular maintenance packages. These offers often include adding brake fluid to the master cylinder reservoir. There are only two reasons why the brake fluid level in the brake reservoir might go down. The first is that the brake fluid level goes down an acceptable level during normal brake lining wear. When the linings are replaced, the fluid will return to it's original level. The second possible reason for a low fluid level is that fluid is leaking out of the brake system. If fluid is leaking, the brake system requires repair and adding additional fluid will not correct the leak. If the system was properly filled during delivery of the vehicle, no additional fluid should be required under most circumstances between brake pad and/or shoe replacements. This information can be reinforced with the customer by referring them to the Brake Fluid section of their vehicle's Owner's Manual. Guidelines GM vehicles have incorporated a variety of brake fluid reservoir styles. The following guidelines are restricted to the plastic bodied fluid reservoirs and do not affect the original service recommendations for the older style metal bodied units. You may encounter both black plastic and translucent style reservoirs. You may have reservoirs with: ^ A MAX fill mark only ^ A MIN fill mark only ^ Both MAX and MIN marks The translucent style reservoirs do not have to have the covers removed in order to view the fluid level. It is a good practice not to remove the reservoir cover unless necessary to reduce the possibility of contaminating the system. Use the following guidelines to assist in determining the proper fluid level. Important: When adding brake fluid, use Delco Supreme II(R) Brake Fluid, GM P/N 12377967 or equivalent brand bearing the DOT-3 rating only. Important: At no time should the fluid level be allowed to remain in an overfilled condition. Overfilling the brake reservoir may put unnecessary stress on the seals and cover of the reservoir. Use the following guidelines to properly maintain the fluid level. If the reservoir is overfilled, siphon out the additional fluid to comply with the guidelines below. Important: If under any circumstance the brake fluid level is extremely low in the reservoir or the BRAKE warning indicator is illuminated, the brake system should be checked for leaks and the system repaired in addition to bringing the fluid level up to the recommended guidelines outlined below. A leaking brake system will have reduced braking performance and will eventually not work at all. Important: Some vehicles have reservoirs that are very sensitive to brake fluid levels and may cause the BRAKE indicator to flicker on turns as the fluid approaches the minimum required level. If you encounter a vehicle with this concern, increase the fluid level staying within the guidelines outlined below. ^ If the reservoir has a MAX level indicator, the reservoir should be returned to the MAX marking only at the time new brake pads and/or shoes are installed. If the reservoir fluid level is at the half-way point or above do not attempt to add additional brake fluid during routine fluid checks. ^ If the reservoir has both MAX and MIN indicators, the fluid level should be maintained above the MIN indicator during routine fluid checks and returned to the MAX indication only after new brake pads and/or shoes are installed. ^ For reservoirs with only a MIN indication, the fluid level should be maintained above the MIN indicator during routine fluid checks. Return the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Brake Fluid > Component Information > Technical Service Bulletins > Brake Fluid - Level & Filling Recommendations > Page 1667 reservoir fluid level to full only after installing new brake pads and/or shoes. A full reservoir is indicated on translucent, snap cover reservoirs by a fluid level even with the top level of the view window imprinted into the side of the reservoir. On screw top models in black or translucent plastic, the full level is just below the bottom of the filler neck. Parts Information Part Number Description 12377967 Brake Fluid Parts are currently available from GMSPO. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Brake Fluid > Component Information > Technical Service Bulletins > Page 1668 Brake Fluid: Specifications Brake System DOT 3 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Clutch Fluid > Component Information > Specifications > Capacity Specifications Clutch Fluid: Capacity Specifications Fill the clutch master cylinder to the "Full" or "MAX" mark on the reservoir. Do not overfill. Caution: Should accidental spillage occur, rinse the area thoroughly with water. Pay special attention to any electrical wires, parts, harnesses, rubber or painted surfaces. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Clutch Fluid > Component Information > Specifications > Capacity Specifications > Page 1673 Clutch Fluid: Fluid Type Specifications Hydraulic Clutch Fluid ........................................................................................................................................ GM P/N 12345347 or DOT 3 Brake Fluid Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information Coolant: Technical Service Bulletins Cooling System - Coolant Recycling Information Bulletin No.: 00-06-02-006D Date: August 15, 2006 INFORMATION Subject: Engine Coolant Recycling and Warranty Information Models: 2007 and Prior GM Passenger Cars and Trucks (Including Saturn) 2007 and Prior HUMMER Vehicles 2005-2007 Saab 9-7X Attention: Please address this bulletin to the Warranty Claims Administrator and the Service Manager. Supercede: This bulletin is being revised to adjust the title and Include Warranty Information. Please discard Corporate Bulletin Number 00-06-02-006C (Section 06 - Engine/Propulsion System). Coolant Reimbursement Policy General Motors supports the use of recycled engine coolant for warranty repairs/service, providing a GM approved engine coolant recycling system is used. Recycled coolant will be reimbursed at the GMSPO dealer price for new coolant plus the appropriate mark-up. When coolant replacement is required during a warranty repair, it is crucial that only the relative amount of engine coolant concentrate be charged, not the total diluted volume. In other words: if you are using two gallons of pre-diluted (50:50) recycled engine coolant to service a vehicle, you may request reimbursement for one gallon of GM Goodwrench engine coolant concentrate at the dealer price plus the appropriate warranty parts handling allowance. Licensed Approved DEX-COOL(R) Providers Important: USE OF NON-APPROVED VIRGIN OR RECYCLED DEX-COOL(R) OR DEVIATIONS IN THE FORM OF ALTERNATE CHEMICALS OR ALTERATION OF EQUIPMENT, WILL VOID THE GM ENDORSEMENT, MAY DEGRADE COOLANT SYSTEM INTEGRITY AND PLACE THE COOLING SYSTEM WARRANTY UNDER JEOPARDY. Shown in Table 1 are the only current licensed and approved providers of DEX-COOL(R). Products that are advertised as "COMPATIBLE" or "RECOMMENDED" for use with DEX-COOL(R) have not been tested or approved by General Motors. Non-approved coolants may degrade the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 1678 coolant system integrity and will no longer be considered a 5 yr/150,000 mile (240,000 km) coolant. Coolant Removal Services/Recycling The tables include all coolant recycling processes currently approved by GM. Also included is a primary phone number and demographic information. Used DEX-COOL(R) can be combined with used conventional coolant (green) for recycling. Depending on the recycling service and/or equipment, it is then designated as a conventional 2 yr/30,000 mile (50,000 km) coolant or DEX-COOL(R) 5 yr/150,000 mile (240,000 km) coolant. Recycled coolants as designated in this bulletin may be used during the vehicle(s) warranty period. DEX-COOL(R) Recycling The DEX-COOL(R) recycling service listed in Table 2 has been approved for recycling waste engine coolants (DEX-COOL) or conventional) to DEX-COOL(R) with 5 yr/150,000 mile (240,000 km) usability. Recycling Fluid Technologies is the only licensed provider of Recycled DEX-COOL(R) meeting GM6277M specifications and utilizes GM approved inhibitor packages. This is currently a limited program being monitored by GM Service Operations which will be expanded as demand increases. Conventional (Green) Recycling Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 1679 Processes shown in the Table 3 are capable of recycling waste engine coolants (DEX-COOL(R) or conventional) to a conventional (green) coolant. Recycling conventional coolant can be accomplished at your facility by a technician using approved EQUIPMENT (listed by model number in Table 3), or by an approved coolant recycling SERVICE which may recycle the coolant at your facility or at an offsite operation. Refer to the table for GM approved coolant recyclers in either of these two categories. Should you decide to recycle the coolant yourself, strict adherence to the operating procedures is imperative. Use ONLY the inhibitor chemicals supplied by the respective (GM approved) recycling equipment manufacturer. Sealing Tablets Cooling System Sealing Tablets (Seal Tabs) should not be used as a regular maintenance item after servicing an engine cooling system. Discoloration of coolant can occur if too many seal tabs have been inserted into the cooling system. This can occur if seal tabs are repeatedly used over the service life of a vehicle. Where appropriate, seal tabs may be used if diagnostics fail to repair a small leak in the cooling system. When a condition appears in which seal tabs may be recommended, a specific bulletin will be released describing their proper usage. Water Quality The integrity of the coolant is dependent upon the quality of DEX-COOL(R) and water. DEX-COOL(R) is a product that has enhanced protection capability as well as an extended service interval. These enhanced properties may be jeopardized by combining DEX-COOL(R) with poor quality water. If you suspect the water in your area of being poor quality, it is recommended you use distilled or de-ionized water with DEX-COOL(R). "Pink" DEX-COOL(R) DEX-COOL(R) is orange in color to distinguish it from other coolants. Due to inconsistencies in the mixing of the dyes used with DEX-COOL(R), some batches may appear pink after time. The color shift from orange to pink does not affect the integrity of the coolant, and still maintains the 5 yr/150,000 mile (240,000 km) service interval. Back Service Only use DEX-COOL(R) if the vehicle was originally equipped with DEX-COOL(R). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 1680 Contamination Mixing conventional green coolant with DEX-COOL(R) will degrade the service interval from 5 yrs./150,000 miles (240,000 km) to 2 yrs./30,000 miles (50,000 km) if left in the contaminated condition. If contamination occurs, the cooling system must be flushed twice immediately and re-filled with a 50/50 mixture of DEX-COOL(R) and clean water in order to preserve the enhanced properties and extended service interval of DEX-COOL(R). After 5 years/150,000 miles (240,000 km) After 5 yrs/150,000 miles (240,000 km), the coolant should be changed, preferably using a coolant exchanger. If the vehicle was originally equipped with DEX-COOL(R) and has not had problems with contamination from non-DEX-COOL(R) coolants, then the service interval remains the same, and the coolant does not need to be changed for another 5 yrs/150,000 miles (240,000 km) Equipment (Coolant Exchangers) The preferred method of performing coolant replacement is to use a coolant exchanger. A coolant exchanger can replace virtually all of the old coolant with new coolant. Coolant exchangers can be used to perform coolant replacement without spillage, and facilitate easy waste collection. They can also be used to lower the coolant level in a vehicle to allow for less messy servicing of cooling system components. It is recommended that you use a coolant exchanger with a vacuum feature facilitates removing trapped air from the cooling system. This is a substantial time savings over repeatedly thermo cycling the vehicle and topping-off the radiator. The vacuum feature also allows venting of a hot system to relieve system pressure. Approved coolant exchangers are available through the GMDE (General Motors Dealer Equipment) program. For refilling a cooling system that has been partially or fully drained for repairs other than coolant replacement, the Vac-N-Fill Coolant Refill Tool (GE-47716) is recommended to facilitate removal of trapped air from the cooling system during refill. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 1681 Coolant: Technical Service Bulletins Engine Coolant - Information on Back Service File In Section: 6 - Engine Bulletin No: 53-62-02 Date: November, 1995 Subject: DEX-COOL(TM) Engine Coolant - Information on Back service Models: 1994-95 Passenger Cars and Trucks A new extended-life engine coolant called DEX-COOL(TM) is currently being used in all General Motors' vehicles (excluding Chevrolet Geo and Saturn). Refer to bulletin 53-62-01 for general service information. Backservice DEX-COOL(TM) may be used in General Motors vehicles originally built with conventional (green) coolant with the following considerations: ^ Vehicles eligible for back service are 1994 and 1995 models (excluding 1994 J Body with 4 cylinder engines). ^ The service interval for DEX-COOL(TM) introduced into an older model vehicle originally built with "green" coolant will be 2 years/30,000 miles (50,000 Km) (not 5 years/100,000 miles (160,000 Km)). ^ All the "green" coolant must be removed from the cooling system by means of a system flush. This may be accomplished with a water flushing device or a GMDE waterless coolant changer (use a unit dedicated to "green" coolant, not DEX-COOL TM). Important: When using a GMDE waterless coolant changer, conduct the procedure twice, once with water, and once with DEX-COOL(TM) Backservice with DEX-COOL(TM) is advocated because of enhanced water pump seal durability experienced with this coolant. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 1682 Coolant: Technical Service Bulletins Extended Life Engine Coolant - DEX-COOL(TM) FILE IN SECTION: 6 - Engine BULLETIN NO.: 53-62-01 DATE: June, 1995 SUBJECT: New Extended Life Engine Coolant Known as DEX-COOL(TM) MODELS: 1995 Passenger Cars and Trucks A new extended life engine coolant known as "DEX-COOL(TM)" will be used in all General Motors vehicles. Some trucks will be filled with DEX-COOL TM beginning in late May; most vehicles will convert in July, 1995 with the remaining vehicles to convert by January, 1996. Most of these vehicles will be 1995 models. All production for 1996 models will utilize DEX-COOL(TM). It is imperative to note the following about DEX-COOL(TM) engine coolant: ^ IT IS ORANGE IN COLOR TO DISTINGUISH IT FROM CONVENTIONAL COOLANT. ^ THE SERVICE CHANGE INTERVAL ON VEHICLES WHICH ARE BUILT WITH DEX-COOL(TM) IS 5 YEARS/100,000 MILES, WHICHEVER OCCURS FIRST. ^ TO MAINTAIN FULL CORROSION PROTECTION DURABILITY, DEX-COOL (TM) MUST NOT BE MIXED WITH CONVENTIONAL (CONTAINING SILICATE) ENGINE COOLANTS. ^ DEX-COOL(TM) IS AN ETHYLENE GYLCOL BASED PRODUCT, THEREFORE, BOIL AND FREEZE PROTECTION ARE MEASURED IN THE SAME FASHION AS CONVENTIONAL COOLANTS. TO FULLY REALIZE ITS MANY ADVANTAGES, DEX-COOL(TM) MUST NEVER BE MIXED WITH CONVENTIONAL COOLANTS. It is particularly important to top-off new vehicles with DEX-COOL(TM) DEX-COOL(TM) forms a protective film on aluminum surfaces, however, if a vehicle with less than 3,000 miles is topped-off with conventional coolant, aluminum corrosion may occur. DEX-COOL(TM) CAN BECOME CONTAMINATED BY INADVERTENTLY TOPPING-OFF WITH CONVENTIONAL COOLANT, ADDING CONVENTIONAL COOLANT TO THE RADIATOR, OR EVEN IF FILL/DRAIN CONTAINERS ARE SHARED BETWEEN COOLANTS. If contamination occurs on a new vehicle (i.e. during vehicle prep), the cooling system must be immediately drained and refilled with DEX-COOL(TM) If contamination with conventional coolant occurs after the vehicle has been driven for at least 3,000 miles, no short-term problems will occur; however, the service change interval will be reduced from 5 years/100,000 miles to 2 years/30,000 miles. More information on DEX-COOL(TM) engine coolant service procedures can be found in the 1996 Service Manuals and a video tape which will be issued by STG. Vehicles which contain DEX-COOL(TM) can be identified by a special underhood label which states "USE DEX-COOL(TM) COOLANT ONLY. .. meeting Spec. 6277M". They may also be identified by the coolant's orange color and the information contained in the Owner's Manual. REGARDING COOLANT RECYCLING Engine coolant recycling is affected by DEX-COOL(TM) as follows. Used DEX-COOL(TM) can be mixed into your "used" conventional coolant storage vessel and the mixture recycled in the same manner as you are accustomed to. This recycled mixture of conventional and DEX-COOL(TM) coolant must be used as a 2 year/30,000 mile conventional coolant and should not be used in vehicles originally equipped with DEX-COOL(TM) When servicing vehicles originally equipped with DEX-COOL(TM), use only Goodwrench-DEX-COOL(TM) Additional research will be conducted to evaluate the feasibility of recycling DEX-COOL(TM) to DEX-COOL(TM) in the near future. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Coolant > Component Information > Technical Service Bulletins > Page 1683 Coolant: Specifications Mixture .......................................................................................................................................................... 50/50 of water and ethylene glycol antifreeze Capacity Without Heavy-Duty Radiator .............................................................................................................................................................. 13.5 liters (14.3 qt) With Heavy-Duty Radiator .................................................................................... ............................................................................... 13.8 liters (14.6 qt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information Fluid - A/T: Technical Service Bulletins A/T - DEXRON(R)-VI Fluid Information INFORMATION Bulletin No.: 04-07-30-037E Date: April 07, 2011 Subject: Release of DEXRON(R)-VI Automatic Transmission Fluid (ATF) Models: 2008 and Prior GM Passenger Cars and Light Duty Trucks 2003-2008 HUMMER H2 2006-2008 HUMMER H3 2005-2007 Saturn Relay 2005 and Prior Saturn L-Series 2005-2007 Saturn ION 2005-2008 Saturn VUE with 4T45-E 2005-2008 Saab 9-7X Except 2008 and Prior Chevrolet Aveo, Equinox Except 2006 and Prior Chevrolet Epica Except 2007 and Prior Chevrolet Optra Except 2008 and Prior Pontiac Torrent, Vibe, Wave Except 2003-2005 Saturn ION with CVT or AF23 Only Except 1991-2002 Saturn S-Series Except 2008 and Prior Saturn VUE with CVT, AF33 or 5AT (MJ7/MJ8) Transmission Only Except 2008 Saturn Astra Attention: DEXRON(R)-VI Automatic Transmission Fluid (ATF) is the only approved fluid for warranty repairs for General Motors transmissions/transaxles requiring DEXRON(R)-III and/or prior DEXRON(R) transmission fluids. Supercede: This bulletin is being revised to update information. Please discard Corporate Bulletin Number 04-07-30-037D (Section 07 - Transmission/Transaxle). MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING The content of this bulletin does not apply to manual transmissions or transfer cases. Any vehicle that previously required DEXRON(R)-III for a manual transmission or transfer case should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case Fluid. Some manual transmissions and transfer cases require a different fluid. Appropriate references should be checked when servicing any of these components. Power Steering Systems should now use P/N 9985010 labeled Power Steering Fluid. Consult the Parts Catalog, Owner's Manual, or Service Information (SI) for fluid recommendations. Some of our customers and/or General Motors dealerships/Saturn Retailers may have some concerns with DEXRON(R)-VI and DEXRON(R)-III Automatic Transmission Fluid (ATF) and transmission warranty claims. DEXRON(R)-VI is the only approved fluid for warranty repairs for General Motors transmissions/transaxles requiring DEXRON(R)-III and/or prior DEXRON(R) transmission fluids (except as noted above). Please remember that the clean oil reservoirs of the J-45096 - Flushing and Flow Tester machine should be purged of DEXRON(R)-III and filled with DEXRON(R)-VI for testing, flushing or filling General Motors transmissions/transaxles (except as noted above). DEXRON(R)-VI can be used in any proportion in past model vehicles equipped with an automatic transmission/transaxle in place of DEXRON(R)-III (i.e. topping off the fluid in the event of a repair or fluid change). DEXRON(R)-VI is also compatible with any former version of DEXRON(R) for use in automatic transmissions/transaxles. DEXRON(R)-VI ATF General Motors Powertrain has upgraded to DEXRON(R)-VI ATF with the start of 2006 vehicle production. Current and prior automatic transmission models that had used DEXRON(R)-III must now only use DEXRON(R)-VI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 1688 All 2006 and future model transmissions that use DEXRON(R)-VI are to be serviced ONLY with DEXRON(R)-VI fluid. DEXRON(R)-VI is an improvement over DEXRON(R)-III in the following areas: * These ATF change intervals remain the same as DEXRON(R)-III for the time being. 2006-2008 Transmission Fill and Cooler Flushing Some new applications of the 6L80 six speed transmission will require the use of the J 45096 Flushing and Flow Tester to accomplish transmission fluid fill. The clean oil reservoir of the machine should be purged of DEXRON(R)-III and filled with DEXRON(R)-VI. Parts Information Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 1689 Fluid - A/T: Technical Service Bulletins A/T - Water Or Coolant Contamination Information INFORMATION Bulletin No.: 08-07-30-035B Date: November 01, 2010 Subject: Information on Water or Ethylene Glycol in Transmission Fluid Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks with Automatic Transmission Supercede: This bulletin is being revised to update model years. Please discard Corporate Bulletin Number 08-07-30-035A (Section 07 - Transmission/Transaxle). Water or ethylene glycol in automatic transmission fluid (ATF) is harmful to internal transmission components and will have a negative effect on reliability and durability of these parts. Water or ethylene glycol in ATF will also change the friction of the clutches, frequently resulting in shudder during engagement or gear changes, especially during torque converter clutch engagement. Indications of water in the ATF may include: - ATF blowing out of the transmission vent tube. - ATF may appear cloudy or, in cases of extreme contamination, have the appearance of a strawberry milkshake. - Visible water in the oil pan. - A milky white substance inside the pan area. - Spacer plate gaskets that appear to be glued to the valve body face or case. - Spacer plate gaskets that appear to be swollen or wrinkled in areas where they are not compressed. - Rust on internal transmission iron/steel components. If water in the ATF has been found and the source of the water entry has not been identified, or if a leaking in-radiator transmission oil cooler is suspected (with no evidence of cross-contamination in the coolant recovery reservoir), a simple and quick test kit is available that detects the presence of ethylene glycol in ATF. The "Gly-Tek" test kit, available from the Nelco Company, should be obtained and the ATF tested to make an accurate decision on the need for radiator replacement. This can help to prevent customer comebacks if the in-radiator transmission oil cooler is leaking and reduce repair expenses by avoiding radiator replacement if the cooler is not leaking. These test kits can be obtained from: Nelco Company Test kits can be ordered by phone or through the website listed above. Orders are shipped standard delivery time but can be shipped on a next day delivery basis for an extra charge. One test kit will complete 10 individual fluid sample tests. For vehicles repaired under warranty, the cost of the complete test kit plus shipping charges should be divided by 10 and submitted on the warranty claim as a net item. The transmission should be repaired or replaced based on the normal cost comparison procedure. Important If water or coolant is found in the transmission, the following components MUST be replaced. - Replace all of the rubber-type seals. - Replace all of the composition-faced clutch plates and/or bands. - Replace all of the nylon parts. - Replace the torque converter. - Thoroughly clean and rebuild the transmission, using new gaskets and oil filter. Important The following steps must be completed when repairing or replacing. Flush and flow check the transmission oil cooler using J 45096. Refer to Corporate Bulletin Number 02-07-30-052F- Automatic Transmission Oil Cooler Flush and Flow Test Essential Tool J 45096 TransFlow. - Thoroughly inspect the engine cooling system and hoses and clean/repair as necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 1690 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 1691 Fluid - A/T: Technical Service Bulletins A/T - DEXRON III Fluid Introduction File In Section: 0 - General Information Bulletin No.: 57-02-01 Date: March, 1995 SERVICE MANUAL UPDATE Subject: Section 0 - General Information - DEXRON(R)-III Transmission Fluid Introduction Models: 1995 and Prior Passenger Cars and Trucks General Motors has phased in a new automatic transmission fluid, DEXRON(R)-III, that does not need replacing under normal service. DEXRON(R)-III is designed to help the transmission deliver the best possible performance under all conditions. Refer to Figure 1. The improvements in DEXRON(R)-III include better friction stability, more high temperature oxidation stability and better material compatibility. DEXRON(R)-III has the same low temperature fluidity as DEXRON(R)-IIE, for better transmission performance in cold weather. DEXRON(R)-IIE and DEXRON(R)-III are fully compatible. DEXRON(R)-III is fully compatible with any General Motors passenger vehicle or light truck with automatic transmission and built since 1949. Dealers should require their supplier to include the DEXRON(R)-III license number on all automatic transmission fluid invoices. Starting February 1, 1994 DEXRON(R)-III was phased into all North American assembly plants. DEXRON(R)-III fluid is available from GMSPO (see fluid numbers below): U.S. 1 Quart 12346143 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 1692 1 Gallon 12346144 55 Gallon 12346145 In Canada 1 Liter 10952622 4 Liter 10952623 200 Liter 10952624 The 1995 Automatic Transmission/Transaxle fluid change intervals are the following: (1994 and prior should use the schedules as written in the Owner's Manual.) If the vehicle is mainly driven under one or more of these conditions: In heavy city traffic where the outside temperature regularly reaches 90°F (32°C) or higher. In hilly or mountainous terrain. When doing frequent trailer towing. Uses such as found in taxi, police car or delivery service. Change the fluid and filter every 50,000 miles (63,000 km). If the vehicle is not used mainly under any of these conditions, the fluid and filter do not require periodic changing for vehicles under 8,600 GVWR. Vehicles over 8,600 GVWR change the fluid and filter every 50,000 miles (83,000 km) regardless of driving conditions. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > Page 1693 Fluid - A/T: Specifications Fluid Type ........................................................................................................................................................ DEXRON-IIE or DEXRON-III auto. trans. Capacity Drain & Refill ........................................................................................................................................ .............................................. 4.7 liters (10.0 pt) Overhaul .................................................................. .......................................................................................................................... 10.6 liters (22.4 pt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - A/T > Component Information > Technical Service Bulletins > Page 1694 Fluid - A/T: Service and Repair NOTE: The following procedure has been modified by a technical service bulletin. 1. Raise and support vehicle. 2. Proceed as follows: a. Loosen transmission mount to support attaching nut. b. Loosen two bolts attaching right side of transmission support to frame rail. c. Remove two bolts attaching left side transmission support to frame rail. d. Using suitable transmission jack, support and slightly raise transmission. e. Slide transmission support rearward enough to access rear oil pan attaching bolts. 3. Place drain pan under transmission oil pan, loosen pan bolts on front of pan, pry carefully with screwdriver to loosen oil pan, and allow fluid to drain. 4. Remove remaining oil pan bolts, oil pan, and gasket. 5. Drain fluid from pan, then clean pan and dry thoroughly with compressed air. 6. Remove oil filter to valve body bolt, then the filter and gasket. 7. Install new filter seal into case, then new filter and attaching bolt. 8. Install new gasket on oil pan, then install oil pan and tighten bolts to specification. 9. Lower vehicle and add five quarts of automatic transmission fluid through filler tube. 10. With selector lever in park and parking brake applied, start engine and let idle. Do not race engine. 11. Move selector lever through each range, return to park position, check fluid, and add additional fluid to bring level between dimples on dipstick. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - M/T > Component Information > Specifications Fluid - M/T: Specifications Fluid Type ........................................................................................................................................................ DEXRON-IIE or DEXRON-III auto. trans. Capacity Drain & Refill ........................................................................................................................................ .............................................. 4.7 liters (10.0 pt) Overhaul .................................................................. .......................................................................................................................... 10.6 liters (22.4 pt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - Differential > Component Information > Technical Service Bulletins > Drivetrain - Recommended Axle Lubricant Fluid - Differential: Technical Service Bulletins Drivetrain - Recommended Axle Lubricant File In Section: 0 - General Information Bulletin No.: 76-02-02A Date: October, 1998 INFORMATION Subject: Recommended Axle Lubricant Models: 1999 and Prior Rear Wheel Drive Passenger Cars, Light and Medium Duty Trucks, and Four Wheel Drive Vehicles This bulletin is being revised to add the 1998 and 1999 Model Years and add Vehicle Line and Recommended Axle Lubricant Information. Please discard Corporate Bulletin Number 76-02-02 (Section 0 - General Information). The following tables provide the latest information on recommended axle lubricant. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - Differential > Component Information > Technical Service Bulletins > Drivetrain - Recommended Axle Lubricant > Page 1702 Parts Information Parts are currently available from GMSPO. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Fluid - Differential > Component Information > Technical Service Bulletins > Page 1703 Fluid - Differential: Specifications Fluid Type Standard Differential ^ SAE 80W-90 GL-5 gear lubricant Limited Slip Differential ^ Lubricant additive (GM P/N 1052358) and ^ SAE 80W-90 GL-5 gear lubricant Capacity Drain and Refill .................................................................................................................................... ................................................. 1.7 liters (3.5 pt) Additive ................................................................... .................................................................................................................... 118 milliliters (4 fl oz) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Engine Oil > Component Information > Technical Service Bulletins > Engine - GM dexos 1 and dexos 2(R) Oil Specifications Engine Oil: Technical Service Bulletins Engine - GM dexos 1 and dexos 2(R) Oil Specifications INFORMATION Bulletin No.: 11-00-90-001 Date: March 14, 2011 Subject: Global Information for GM dexos1(TM) and GM dexos2(TM) Engine Oil Specifications for Spark Ignited and Diesel Engines, Available Licensed Brands, and Service Fill for Adding or Complete Oil Change Models: 2012 and Prior GM Passenger Cars and Trucks Excluding All Vehicles Equipped with Duramax(TM) Diesel Engines GM dexos 1(TM) Information Center Website Refer to the following General Motors website for dexos 1(TM) information about the different licensed brands that are currently available: http://www.gmdexos.com GM dexos 1(TM) Engine Oil Trademark and Icons The dexos(TM) specification and trademarks are exclusive to General Motors, LLC. Only those oils displaying the dexos‹›(TM) trademark and icon on the front label meet the demanding performance requirements and stringent quality standards set forth in the dexos‹›(TM) specification. Look on the front label for any of the logos shown above to identify an authorized, licensed dexos 1(TM) engine oil. GM dexos 1(TM) Engine Oil Specification Important General Motors dexos 1(TM) engine oil specification replaces the previous General Motors specifications GM6094M, GM4718M and GM-LL-A-025 for most GM gasoline engines. The oil specified for use in GM passenger cars and trucks, PRIOR to the 2011 model year remains acceptable for those previous vehicles. However, dexos 1(TM) is backward compatible and can be used in those older vehicles. In North America, starting with the 2011 model year, GM introduced dexos 1(TM) certified engine oil as a factory fill and service fill for gasoline engines. The reasons for the new engine oil specification are as follows: - To meet environmental goals such as increasing fuel efficiency and reducing engine emissions. - To promote long engine life. - To minimize the number of engine oil changes in order to help meet the goal of lessening the industry's overall dependence on crude oil. dexos 1(TM) is a GM-developed engine oil specification that has been designed to provide the following benefits: - Further improve fuel economy, to meet future corporate average fuel economy (CAFE) requirements and fuel economy retention by allowing the oil to maintain its fuel economy benefits throughout the life of the oil. - More robust formulations for added engine protection and aeration performance. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Engine Oil > Component Information > Technical Service Bulletins > Engine - GM dexos 1 and dexos 2(R) Oil Specifications > Page 1708 - Support the GM Oil Life System, thereby minimizing the replacement of engine oil, before its life has been depleted. - Reduce the duplication of requirements for a large number of internal GM engine oil specifications. International Lubricants Standardization and Approval Committee (ILSAC) GF-5 Standard In addition to GM dexos 1(TM), a new International Lubricants Standardization and Approval Committee (ILSAC) standard called GF-5, was introduced in October 2010. - There will be a corresponding API category, called: SN Resource Conserving. The current GF-4 standard was put in place in 2004 and will become obsolete in October 2011. Similar to dexos 1(TM), the GF-5 standard will use a new fuel economy test, Sequence VID, which demands a statistically significant increase in fuel economy versus the Sequence VIB test that was used for GF-4. - It is expected that all dexos 1(TM) approved oils will be capable of meeting the GF-5 standard. However, not all GF-5 engine oils will be capable of meeting the dexos 1(TM) specification. - Like dexos(TM), the new ILSAC GF-5 standard will call for more sophisticated additives. The API will begin licensing marketers during October 2010, to produce and distribute GF-5 certified products, which are expected to include SAE 0W-20, 0W-30, 5W-20, 5W-30 and 10W-30 oils. Corporate Average Fuel Economy (CAFE) Requirements Effect on Fuel Economy Since CAFE standards were first introduced in 1974, the fuel economy of cars has more than doubled, while the fuel economy of light trucks has increased by more than 50 percent. Proposed CAFE standards call for a continuation of increased fuel economy in new cars and trucks. To meet these future requirements, all aspects of vehicle operation are being looked at more critically than ever before. New technology being introduced in GM vehicles designed to increase vehicle efficiency and fuel economy include direct injection, cam phasing, turbocharging and active fuel management (AFM). The demands of these new technologies on engine oil also are taken into consideration when determining new oil specifications. AFM for example can help to achieve improved fuel economy. However alternately deactivating and activating the cylinders by not allowing the intake and exhaust valves to open contributes to additional stress on the engine oil. Another industry trend for meeting tough fuel economy mandates has been a shift toward lower viscosity oils. dexos 1(TM) will eventually be offered in several viscosity grades in accordance with engine needs: SAE 0W-20, 5W-20, 0W-30 and 5W-30. Using the right viscosity grade oil is critical for proper engine performance. Always refer to the Maintenance section of a vehicle Owner Manual for the proper viscosity grade for the engine being serviced. GM Oil Life System in Conjunction With dexos (TM) Supports Extended Oil Change Intervals To help conserve oil while maintaining engine protection, many GM vehicles are equipped with the GM Oil Life System. This system can provide oil change intervals that exceed the traditional 3,000 mile (4,830 km) recommendation. The dexos (TM) specification, with its requirements for improved oil robustness, compliments the GM Oil Life System by supporting extended oil change intervals over the lifetime of a vehicle. If all GM customers with GM Oil Life System equipped vehicles would use the system as intended, GM estimates that more than 100 million gallons of oil could be saved annually. GM dexos 2(TM) Information Center Website Refer to the following General Motors website for dexos 2(TM) information about the different licensed brands that are currently available: http://www.gmdexos.com GM dexos 2(TM) Engine Oil Trademark and Icons Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Engine Oil > Component Information > Technical Service Bulletins > Engine - GM dexos 1 and dexos 2(R) Oil Specifications > Page 1709 The dexos (TM) specification and trademarks are exclusive to General Motors, LLC. Only those oils displaying the dexos (TM) trademark and icon on the front label meet the demanding performance requirements and stringent quality standards set forth in the dexos (TM)specification. Look on the front label for any of the logos shown above to identify an authorized, licensed dexos 2(TM) engine oil. GM dexos 2(TM) Engine Oil Specification - dexos 2(TM) is approved and recommended by GM for use in Europe starting in model year 2010 vehicles, regardless of where the vehicle was manufactured. - dexos 2(TM) is the recommended service fill oil for European gasoline engines. Important The Duramax(TM) diesel engine is the exception and requires lubricants meeting specification CJ-4. - dexos 2(TM) is the recommended service fill oil for European light-duty diesel engines and replaces GM-LL-B-025 and GM-LL-A-025. - dexos 2(TM) protects diesel engines from harmful soot deposits and is designed with limits on certain chemical components to prolong catalyst life and protect expensive emission reduction systems. It is a robust oil, resisting degradation between oil changes and maintaining optimum performance longer. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Engine Oil > Component Information > Specifications > Capacity Specifications Engine Oil: Capacity Specifications Fluid Type ............................................................................................................................................ .................................................. API service SH/SG Capacity Without filter change ............................................................................................................................ ................................................. 3.8 liters (4.0 qt) With filter change .................................................... .............................................................................................................................. 4.7 liters (5.0 qt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment Refrigerant: Technical Service Bulletins A/C - Refrigerant Recovery/Recycling/Equipment Bulletin No.: 08-01-38-001 Date: January 25, 2008 INFORMATION Subject: Information On New GE-48800 CoolTech Refrigerant Recovery/Recharge Equipment Models: 2008 and Prior GM Passenger Cars and Light Duty Trucks (Including Saturn) 2008 and Prior HUMMER H2, H3 2005-2008 Saab 9-7X Attention: This bulletin is being issued to announce the release of GM approved Air Conditioning (A/C) Refrigerant Recovery and Recharging Equipment that meets the new Society of Automotive Engineers (SAE) J2788 Refrigerant Recovery Standards. The ACR2000 (J-43600) cannot be manufactured in its current state after December 2007 and will be superseded by GE-48800. The new J2788 standard does not require that GM Dealers replace their ACR2000 units. ACR2000's currently in use are very capable of servicing today's refrigerant systems when used correctly and can continue to be used. Details regarding the new SAE J2788 standard are outlined in GM Bulletin 07-01-38-004. Effective February 1 2008, new A/C Refrigerant Recovery/Recharging equipment (P/N GE-48800) will be released as a required replacement for the previously essential ACR2000 (J-43600). This equipment is SAE J2788 compliant and meets GM requirements for A/C Refrigerant System Repairs on all General Motors vehicles, including Hybrid systems with Polyolester (POE) refrigerant oil. This equipment will not be shipped as an essential tool to GM Dealerships. In addition, this equipment is Hybrid compliant and designed to prevent oil cross contamination when servicing Hybrid vehicles with Electric A/C Compressors that use POE refrigerant oil. The ACR2000 (J-43600) will need to be retrofitted with a J-43600-50 (Hose - ACR2000 Oil Flush Loop) to be able to perform Hybrid A/C service work. All Hybrid dealers will receive the J-43600-50, with installation instructions, as a component of the Hybrid essential tool package. Dealerships that do not sell Hybrids, but may need to service Hybrids, can obtain J-43600-50 from SPX Kent Moore. Refer to GM Bulletin 08-01-39-001 for the ACR2000 Hose Flush procedure. The High Voltage (HV) electric A/C compressor used on Two Mode Hybrid vehicles uses a Polyolester (POE) refrigerant oil instead of a Polyalkylene Glycol (PAG) synthetic refrigerant oil. This is due to the better electrical resistance of the POE oil and its ability to provide HV isolation. Failure to flush the hoses before adding refrigerant to a Hybrid vehicle with an electric A/C compressor may result in an unacceptable amount of PAG oil entering the refrigerant system. It may cause a Battery Energy Control Module Hybrid Battery Voltage System Isolation Lost Diagnostic Trouble Code (DTC P1AE7) to be set. Additionally, the A/C system warranty will be voided. Warranty Submission Requirements The Electronically Generated Repair Data (snapshot summary) and printer functions have been eliminated from the GE-48800. The VGA display and temperature probes were eliminated to reduce equipment costs. As a result, effective immediately the 18 digit "Snapshot/Charge Summary" code is no longer required for Air Conditioning (A/C) refrigerant system repairs that are submitted for warranty reimbursement. The charge summary data from before and after system repairs will continue to required, but documented on the repair order only. Both high and low pressures and the recovery and charge amounts should be noted during the repair and entered on the repair order. If using ACR2000 (J-43600), the "Snapshot/Charge Summary" printouts should continue to be attached to the shops copy of the repair order. The labor codes that are affected by this requirement are D3000 through D4500. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1716 Refrigerant: Technical Service Bulletins A/C - Contaminated R134A Refrigerant Bulletin No.: 06-01-39-007 Date: July 25, 2006 INFORMATION Subject: Contaminated R134a Refrigerant Found on Market for Automotive Air-Conditioning Systems Models: 2007 and Prior GM Passenger Cars and Trucks (including Saturn) 2007 and Prior HUMMER H2, H3 2007 and Prior Saab 9-7X Attention: This bulletin should be directed to the Service Manager as well as the Parts Manager. Commercially Available Contaminated R134a Refrigerant Impurities have been found in new commercially available containers of R134a. High levels of contaminates may cause decreased performance, and be detrimental to some air-conditioning components. Accompanying these contaminates has been high levels of moisture. Tip: Excessive moisture may cause system concerns such as orifice tube freeze-up and reduced performance. Industry Reaction: New Industry Purity Standards Due to the potential availability of these lower quality refrigerants, the Society of Automotive Engineers (SAE), and the Air Conditioning and Refrigeration Industry (ARI) are in the process of instituting reliable standards that will be carried on the labels of future R134a refrigerant containers. This identifying symbol will be your assurance of a product that conforms to the minimum standard for OEM Automotive Air-Conditioning use. How Can You Protect Yourself Today? It is recommended to use GM or ACDelco(R) sourced refrigerants for all A/C repair work. These refrigerants meet General Motors own internal standards for quality and purity, insuring that your completed repairs are as good as the way it left the factory. Parts Information The part numbers shown are available through GMSPO or ACDelco(R). The nearest ACDelco(R) distributor in your area can be found by calling 1-800-223-3526 (U.S. Only). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1717 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1718 Refrigerant: Technical Service Bulletins A/C - Refrigerant Recovery/Recharge Equipment File In Section: 01 - HVAC Bulletin No.: 99-01-38-006A Date: May, 2000 WARRANTY ADMINISTRATION Subject: J-43600 ACR 2000 Essential Refrigerant Recovery/Recharge Equipment Models: 1993-2000 Passenger Cars and Light Duty Trucks with R-134a Refrigerant This bulletin is being revised to change the effective date and to update the text. Please discard Corporate Bulletin Number 99-01-38-006 (Section 01 - HVAC). Effective June 1, 2000, the use of J-43600 ACR 2000 will be required on all repairs that require A/C system recovery and are reimbursable by GM. Additionally, GM highly recommends that J-43600 ACR 2000 be used on all GM cars and trucks for customer paid A/C repairs. Important: Also effective June 1, 2000, the "Add" time for all air conditioning recovery is revised to 0.5 hours for front systems and 0.7 hours for front/rear dual systems (RPO C69 or C34). After June 1, 2000, all air conditioning claims submitted with the 0.9 hours "Add" time will be rejected for "labor hours excessive". After the completion of repairs (charging), the ACR 2000 will prompt the user to perform a snapshot of the air conditioning system operating data. The snapshot includes: ^ Maximum high side pressure. ^ Minimum low side pressure. ^ Duct outlet temperatures (2). ^ Refrigerant purity information. This information is captured on a paper printout and in a warranty code. For all GM paid repairs, the paper printout should be attached to the shop copy of the repair order. The warranty code must be submitted in the warranty claim information in the comments field. The code enables the reporting of valuable information about the repair to GM for product quality improvement. Claims submitted without this information may be subject to review and subsequent debit. The required use of J-43600 ACR 2000 raises the question of the acceptable uses for any existing recovery/recycle equipment that GM dealers are currently using. GM recognizes that many of the previously essential ACR4's are reaching the end of their useful life. There are several alternatives for existing equipment that may be considered: ^ Use the existing equipment as customer paid recovery only equipment. Example: Collision repair area. ^ Use the existing equipment as a scavenger unit for contaminated A/C systems. ^ Sell the existing units to repair facilities outside the GM dealer network. ^ Discontinue the use of the existing units if the repair/maintenance costs exceed the value of the equipment. ^ Donate the existing equipment to local technical schools. ^ Dedicate the ACR4 to A/C system flushing, using the J-42939 Flush Adapter. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1719 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1720 Technical Service Bulletin # 631209 Date: 960501 A/C - R12 or R134a Service Recommendations File In Section: 1 - HVAC Bulletin No.: 63-12-09 Date: May, 1996 INFORMATION Subject: Service Issues for Vehicles with R12 or R134a Air Conditioning Systems Models: 1988-96 Passenger Cars and Trucks R12 Service Recommendations As you know, production of R12 refrigerant ceased on December 31, 1995. Although R12 will no longer be manufactured, there is a reserve supply of R12 available. This reserve, along with strict A/C repair service adherence to proper refrigerant recycling procedures, should assure continued availability to meet consumers' needs. R12 can and should continue to be used to service vehicles built with R12 A/C systems as long as it is available. If R12 is no longer available or affordable, a system retrofit utilizing R134a is recommended. R134a IS THE ONLY SUBSTITUTE REFRIGERANT RECOMMENDED BY GM FOR USE IN GM VEHICLE A/C SYSTEMS, AND THEN ONLY AFTER FOLLOWING THE PROPER RETROFIT PROCEDURES FOR THE SPECIFIC MODEL. All new vehicle manufacturers have chosen R134a for retrofit. One of the key reasons is to protect both the service industry and consumers from the high costs that would result from purchasing equipment necessary to service multiple refrigerants. This position also reduces the threat of recycled refrigerant contamination. GM currently offers a simple, low cost R12 to R134a retrofit on many of its late model, front wheel drive passenger cars. Dealers should discuss this capability with owners of these specific models, listed in Retrofit Corporate Bulletin # 43-12-07D, whenever a repair to the A/C refrigerant system is required. Early retrofit of these specific models will aid in prolonging availability of the R12 supply and provide dealer service technicians the opportunity to become more familiar with the proper procedures for performing a retrofit. Remember - R12 and R134a refrigerant are not interchangeable! They cannot be mixed together. In fact, despite the claims of some refrigerant manufacturers, no proposed R12 refrigerant substitute can be added to, mixed with or used to "top off" an R12 system. Under provisions of law covering the service of refrigerants, mixing dissimilar refrigerant products during service is prohibited. To Summarize GM R12 Service Policy 1. Service R12 vehicles with good quality new or recycled R12 as long as it is available. 2. Purchase R12 from a reliable supplier. GMSPO has a supply of high quality R12 available. Dealers are requested to use only R12 supplied by GMSPO for warranty repairs. This high quality refrigerant will insure system performance and avoid the possibility of introducing contaminated material into the customer's A/C system. 3. Carefully test recovered R12 using the PureGuard monitor. On recovery equipment not protected by the PureGuard, always test the recovery cylinder prior to recharging a vehicle A/C system. 4. Discuss the R12 to R134a retrofit option with owners of GM vehicles listed in Retrofit Corporate Bulletin # 43-12-07D. Provide owner with a copy of the pamphlet "Converting Your Auto Air Conditioning System to Use the New Refrigerant". 5. Become familiar with retrofit procedures and exercise care in the handling of dissimilar refrigerants to prevent contamination. R134A Service Recommendations When servicing a previously retrofitted vehicle, there is concern that if all of the R12 is not completely removed prior to the retrofit procedure, it could contaminate your R134a equipment and recovery tank when a subsequent A/C repair is performed. Although the number of retrofits being performed today is minimal, the volume will increase as R12 prices rise. GM Service Technology Group is in the process of field testing a new R134a refrigerant purity tester similar to the PureGuard R12 refrigerant tester you now use. This new tool will mount to your ACR4 R134a Recovery Recycle and Recharge cart and sample all R134a refrigerant prior to recovery. It is expected that testing of this tool will be completed this year. This new tool, the Pureguard 2, will also test vehicles and your recycle tank for air contamination, which is threatening A/C system performance. High levels of air have been found in the recovery tanks on a number of R12 and R134a recovery carts. Air contamination is caused by improper recovery Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1721 procedures and short-cutting refrigerant recycling times. Use the following procedure for testing and correcting air contamination in your A/C service equipment. 1. Make certain that the ACR4 equipment has not been used for at least 12 hours. It is recommended that the equipment be left in an area where the temperature will remain constant overnight to allow the temperature of the refrigerant in the tank to stabilize. 2. Record the surrounding air temperature next to the ACR4 refrigerant tank. Important: A major assumption is that the ambient air temperature next to the tank represents the refrigerant temperature in the tank. Failure to take care in measuring the temperature could result in unnecessary work. 3. Close both liquid (blue) and vapor (red) valves on the ACR4 tank. 4. Disconnect low side (blue) service hose from the back of the ACR4. 5. Slowly disconnect the tank vapor hose (red) from the back of the ACR4 and connect it to the low side service port. 6. Open the vapor (red) valve on the tank and record the tank pressure on the low side gage. 7. Restore hoses to the original position. 8. Referring to the Table, find the ambient temperature measured in Step 2. Compare the pressure reading from Step 6 to the "maximum allowable pressure". If the pressure reading from Step 6 is less than the "maximum allowable pressure", no further action is necessary. Important: The closer the tank pressure is to the desired tank pressure, the better the A/C system will perform. 9. If the pressure reading from Step 6 exceeds the maximum allowable pressure from the Table, open both tank valves and operate the ACR4 through 4 or 5 evacuation cycles. This will activate the automatic air purge to lower the tank pressure. Important: Station should not be connected to vehicle. 10. Repeat the tank pressure checking procedure the next day to determine if the pressure has been reduced to acceptable levels. If the tank pressure has been reduced but is not acceptable, cycle with ACR4 through more evacuation cycles and recheck the next day. Continue process until acceptable pressure is obtained. If the tank pressure is not reduced through the evacuation cycling, then Kent-Moore should be contacted at 1-800-345-2233. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1722 Refrigerant: Technical Service Bulletins A/C - R134a Leak Detection With Tracer Dye File In Section: 1 - HVAC Bulletin No.: 43-12-15 Date: November, 1994 Subject: R134a Leak Detection with Tracer Dye Models: All 1993-95 Vehicles with OEM R134a Systems All R12 Vehicles Retrofitted to R134a Systems R134a refrigerant is uniquely different from R12 refrigerant and requires some changes in the repair methods, tools and materials used in A/C service. Two important differences between R134a and R12 which affect the technicians ability to locate refrigerant leaks are: 1. The R134a molecule is smaller than the R12 molecule and therefore will leak through smaller openings. For the same size opening the smaller R134a molecule will leak out faster than the R12. 2. R134a refrigerant does not contain chlorine which the older R12 electronic leak detectors found very easy to identify. Many of today's electronic leak detectors have difficulty locating small R134a refrigerant leaks. In order to insure the highest quality in A/C system service, the J 39400 electronic leak detector was released as an essential tool for all GM dealers. This is the only refrigerant leak detector approved by GM for service on R134a vehicles. If maintained properly (Reference Bulletin No. 431218) and used in accordance with Service Manual procedures, the J 39400 will provide the most accurate and efficient method of locating R134a refrigerant leaks under most conditions. If the technician cannot find the leak with the J 39400 and the system is known to have lost charge, a new fluorescent leak tracer dye Kent-Moore* P/N J 41447, has been released that mixes with the R134a PAG oil. This dye is detectable through the use of an ultraviolet (black) light and glows yellow/green at the leak location (similar to using dye in engine leak detection). J 41447 IS THE ONLY APPROVED DYE BY GENERAL MOTORS. Not all R134a dyes are compatible with GM's PAG oil. Some dyes decrease the oil viscosity or chemically react with the oil. Use of alternate products may affect system reliability and cause premature compressor failure. Note: THIS DYE IS NOT TO BE USED IN R-12 SYSTEMS. Unlike mineral oil, the R134a PAG oil has special properties the technician should keep in mind. 1. PAG oil is water soluble and traces of PAG oil found at leaking joints are subject to "washing out". Condensation on refrigerant lines or the evaporator core may wash the PAG oil and leak dye off the line or off the core and out the condensate drain. This can make some leaks harder to find using the dye detector. Fluorescence at the drain opening would indicate a core leak. 2. Use of the R134a tracer dye requires time. Depending upon the leak rate, it may take between 15 minutes and 7 days for the leak to become visible. 3. The dye, mixed with the PAG oil, is retained in the system and is detectable for 2+ years. Do not double or triple charge the system with dye as this may cause reliability concerns. Use only the 1/4 oz. charge. The dye has a refrigerant leak detection notice sticker included with the package. Complete the sticker information and place near the charge label. Dye Injection R-134a dye can be injected two ways: 1. With the A/C system charged, use the instructions provided with the new R134a leak dye injection tool, J 41436. 2. With A/C system discharged, add dye into the newly replaced component assembly. It is important to note that it is normal to find oil traces at the compressor shaft seal during compressor operation, some oil will hydraulically seep past the shaft seal. This does not mean that the shaft seal is defective or that the refrigerant has leaked. Refrigerant leaks at the shaft seal should be verified with the electronic leak detector (J 39400) following the procedure detailed in the Service Manual. If, however, the amount of oil is excessive, the shaft seal is suspect and should be replaced. (For example, refrigerant oil has coated the clutch plate edge at gap between clutch and pulley, or oil slinging has occurred-oil line shows on underside of hood, etc.). Also, after working on A/C components with dye, it is important to wipe the joint and/or access ports clean of any residual dye with GM solvent (GM Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 1723 P/N 1050436) to prevent false diagnosis at a later point. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Parts Information GM solvent, P/N 1050436, is currently available from GMSPO. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Technical Service Bulletins > Page 1724 Refrigerant: Specifications Refrigerant Capacity, Lbs. ................................................................................................................... ................................................ 0.79 kg. (1 lb. 12 oz.) Refrigerant Type .................................................................................................................................. ...................................................................... R-134a Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Description and Operation > Refrigerant R-12 Refrigerant: Description and Operation Refrigerant R-12 DESCRIPTION It is colorless and odorless both as a gas and a liquid. Since it boils (vaporizes) at -21.7° F, it will usually be in a vapor state when being handled in a repair shop. But if a portion of the liquid coolant should come in contact with the hands or face, note that its temperature momentarily will be at least -22° F. WARNING: Protective goggles should be worn when opening any refrigerant lines. If liquid coolant does touch the eyes, bathe the eyes quickly in cold water, then apply a bland disinfectant oil to the eyes. See an eye doctor. WARNING: When checking a system for leaks with a torch type leak detector, do not breathe the vapors coming from the flame. Do not discharge refrigerant in the area of a live flame. A poisonous phosgene gas is produced when R-12 is burned. While the small amount of gas produced by a leak detector is not harmful unless inhaled directly at the flame, the quantity of refrigerant released into the air when a system is purged can be extremely dangerous if allowed to come into contact with an open flame. WARNING: Never allow the temperature of refrigerant drums to exceed 125° F. The excessive increase in temperature will cause a corresponding increase in pressure which may cause the safety plug to release or the drum to burst. If it is necessary to heat a drum of refrigerant when charging a system, the drum should be placed in water no hotter than 125° F. Never use a blow torch or other open flame. If possible, a pressure release mechanism should be attached before the drum is heated. When connecting and disconnecting service gauges on an A/C system, ensure gauge hand valves are fully closed and that compressor service valves, if equipped, are in the back-seated (fully counterclockwise) position. Do not disconnect gauge hoses from service port adapters, if used, while gauges are connected to A/C system. To disconnect hoses, always remove adapter from service port. Do not disconnect hoses from gauge manifold while connected to A/C system, as refrigerant will be rapidly discharged. After disconnecting gauge lines, check the valve areas to be sure service valves are correctly seated and Schrader valves, if used, are not leaking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant > Component Information > Description and Operation > Refrigerant R-12 > Page 1727 Refrigerant: Description and Operation Refrigerant-134a R-134a refrigerant is a non toxic, nonflammable, clear and odorless liquefied gas. CAUTION: R-134a refrigerant is not compatible with R-12 refrigerant. Even small amounts of R-12 in a R-134a system will cause lubricant contamination, compressor failure or improper A/C performance. Never add R-12 to a R-134a system. WARNING: Avoid breathing R-134a refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose and throat. Use only approved service equipment to discharge R-134a systems. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant Oil > Component Information > Technical Service Bulletins > A/C - New PAG Oil Refrigerant Oil: Technical Service Bulletins A/C - New PAG Oil Bulletin No.: 02-01-39-004B Date: November 16, 2005 INFORMATION Subject: New PAG Oil Released Models: 2006 and Prior GM Passenger Cars and Trucks (Including Saturn) 2003-2006 HUMMER H2 2006 HUMMER H3 2005-2006 Saab 9-7X Built With R-134a Refrigeration System All Air Conditioning Compressor Types (Excluding R4 and A6 Type Compressors) Supercede: This bulletin is being revised to change the PAG oil part number used for R4 and A6 compressors with R-134a refrigerant systems. Please discard Corporate Bulletin Number 02-01-39-004A (Section 01 - HVAC). All General Motors vehicles built with R-134a refrigerant systems shall now be serviced with GM Universal PAG Oil (excluding vehicles equipped with an R4 or A6 compressor). R4 and A6 compressors with R-134a refrigerant systems shall use PAG OIL, GM P/N 12356151 (A/C Delco part number 15-118) (in Canada, use P/N 10953486). Important: The PAG oil referenced in this bulletin is formulated with specific additive packages that meet General Motors specifications and use of another oil may void the A/C systems warranty. Use this new PAG oil when servicing the A/C system on the vehicles listed above. Oil packaged in an 8 oz tube should be installed using A/C Oil Injector, J 45037. Refer to the HVAC Section of Service Information for detailed information on Oil Balancing and Capacities. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant Oil > Component Information > Specifications > Capacity Specifications Refrigerant Oil: Capacity Specifications Compressor Model [02] ....................................................................................................................... ........................................................... HD6/HR6-HE Oil Charge (FL. Oz.) When Replacing Component Compressor ......................................................................................................................................... ............................................................................. [03] Evaporator ........................................................................................................................................... ................................................................................. 3 Condenser ...................................................... .............................................................................................................................................................. ........ 1 Accumulator ............................................................................................................................. ......................................................................................... 3.5 [02] Fixed displacement compressor. [03] Drain oil from old compressor and measure, then drain new compressor. If more than one ounce is drained from old compressor, add same amount to new compressor. If less than one ounce is drained from compressor, add two ounces. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fluids > Refrigerant Oil > Component Information > Specifications > Capacity Specifications > Page 1734 Refrigerant Oil: Fluid Type Specifications REFRIGERANT OIL TYPE ^ R-134a PAG (Polyalkaline Glycol) synthetic refrigerant oil (GM Part No. 12345923) or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Brake Bleeding > System Information > Service and Repair > With ABS System Brake Bleeding: Service and Repair With ABS System Manual Bleeding Fig. 210 Brake System Manual Bleed. NOTE: Pressure bleeding is recommended for all hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure. CAUTION: Brake fluid damages painted surfaces. Immediately clean any spilled fluid. 1. Remove vacuum reserve by pumping brakes several times with engine off. 2. Fill master cylinder reservoir with clean brake fluid. Check fluid level often during bleeding procedure; do not let reservoir fall below half full. 3. If necessary, bleed master cylinder as follows: a. Disconnect master cylinder forward brake line connection until fluid flows from reservoir. Reconnect and tighten brake line. b. Instruct an assistant to slowly depress brake pedal one time and hold. c. Crack open front brake line connection again, purging air from cylinder. d. Retighten connection and slowly release brake pedal. e. Wait 15 seconds, then repeat until all air is purged. f. Bleed the rearward (nearest the cowl) brake line connection by repeating preceding steps. 4. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 5. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleed Sequence. See: Wheel Bleed Sequence 6. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 210. Ensure end of tube is submerged in clean brake fluid. 7. Instruct an assistant to slowly depress brake pedal one time and hold. 8. Crack open bleeder valve, purging air from cylinder. Retighten bleeder screw and slowly release pedal. 9. Wait 15 seconds, then repeat preceding bleed steps. Repeat these steps until all air is bled from system. Pressure Bleeding Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 1739 Fig. 210 Brake System Manual Bleed. Fig. 21 Installing Pressure Bleeder Adapter 1. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 2. Using a diaphragm type pressure bleeder, install suitable bleeder adapter to master cylinder, Fig. 211. 3. Charge bleeder ball to 20-25 psi. 4. Connect pressure bleeder line to adapter. 5. Open line valve on pressure bleeder, then depress bleed-off valve on adapter until a small amount of brake fluid is released. 6. Raise and support vehicle. 7. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. See: Wheel Bleed Sequence 8. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 210. Ensure end of tube is submerged in clean brake fluid. 9. Open bleeder valve 1/2 to 3/4 turn and allow fluid to flow into container until all air is purged from line. Wheel Bleed Sequence If manual bleeding, RR-LR-RF-LF; if pressure bleeding, bleed front brakes together and rear brakes together. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 1740 Brake Bleeding: Service and Repair Without ABS System Manual Fig. 210 Brake System Manual Bleed. NOTE: Pressure bleeding is recommended for all hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure. Brake fluid damages painted surfaces. Immediately clean any spilled fluid. 1. Remove vacuum reserve by pumping brakes several times with engine off. 2. Fill master cylinder reservoir with clean brake fluid. Check fluid level often during bleeding procedure; do not let reservoir fall below half full. 3. If necessary, bleed master cylinder as follows: a. Disconnect master cylinder forward brake line connection until fluid flows from reservoir. Reconnect and tighten brake line. b. Instruct an assistant to slowly depress brake pedal one time and hold. c. Crack open front brake line connection again, purging air from cylinder. d. Retighten connection and slowly release brake pedal. e. Wait 15 seconds, then repeat until all air is purged. f. Bleed the rearward (nearest the cowl) brake line connection by repeating steps a through e. 4. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 5. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. 6. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 16. Ensure end of tube is submerged in clean brake fluid. 7. Instruct an assistant to slowly depress brake pedal one time and hold. 8. Crack open bleeder valve, purging air from cylinder. Retighten bleeder screw and slowly release pedal. 9. Wait 15 seconds, then repeat steps 7 and 8. Repeat these steps until all air is bled from system. Pressure Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 1741 Fig. 21 Installing Pressure Bleeder Adapter Fig. 210 Brake System Manual Bleed. 1. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 2. Using a diaphragm type pressure bleeder, install suitable bleeder adapter to master cylinder, Fig. 17. 3. Charge bleeder ball to 20-25 psi. 4. Connect pressure bleeder line to adapter. 5. Open line valve on pressure bleeder, then depress bleed-off valve on adapter until a small amount of brake fluid is released. 6. Raise and support vehicle. 7. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. 8. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 16. Ensure end of tube is submerged in clean brake fluid. 9. Open bleeder valve 1/2 to 3/4 turn and allow fluid to flow into container until all air is purged from line. Front Disc Brakes NOTE: Pressure bleeding is recommended for all hydraulic disc brake systems. The disc brake hydraulic system can be bled manually or with pressure bleeding equipment. On vehicles with disc brakes the brake pedal will require more pumping and frequent checking of fluid level in master cylinder during bleeding operation. Never use brake fluid that has been drained from hydraulic system when bleeding the brakes. Be sure the disc brake pistons are returned to their normal positions and that the shoe and lining assemblies are properly seated. Before driving the vehicle, check brake operation to be sure that a firm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 1742 pedal has been obtained. Rear Disc Brakes NOTE: Pressure bleeding is recommended for all hydraulic disc brake systems. The disc brake hydraulic system can be bled manually or with pressure bleeding equipment. On vehicles with disc brakes the brake pedal will require more pumping and frequent checking of fluid level in master cylinder during bleeding operation. Never use brake fluid that has been drained from hydraulic system when bleeding the brakes. Be sure the disc brake pistons are returned to their normal positions and that the shoe and lining assemblies are properly seated. Before driving the vehicle, check brake operation to be sure that a firm pedal has been obtained. Wheel Bleeding Sequence Rear wheel drive models: if manual bleeding, RR-LR-RF-LF; if pressure bleeding, bleed front brakes together and rear brakes together. Front wheel drive models: RR-LF-LR-RF Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming Air Bag(s) Arming and Disarming: Service and Repair Air Bag Disarming and Arming Disabling the SIR System The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Ensure front wheels are pointed straight ahead. 2. Turn ignition switch to LOCK position and remove SIR or AIR BAG fuse. 3. Remove Connector Position Assurance (CPA), then disconnect both yellow 2-way SIR electrical connectors at base of steering column. 4. Wait at least 2 minutes before proceeding with diagnosis or service. Enabling the SIR System 1. Connect both 2-way yellow connectors at base of steering column. 2. Install Connector Position Assurance (CPA). 3. Install SIR or AIR BAG fuse into fuse block. 4. Turn ignition to the RUN position and ensure that the "Inflatable Restraint lamp flashes seven to nine times and then turns off. If lamp does not operate as specified, refer to Testing And Inspection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming > Page 1747 Air Bag(s) Arming and Disarming: Service and Repair General Service Precautions CAUTION; When performing service on or around SIR components or SIR wiring, follow the procedures to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Circuit Breaker > Component Information > Locations Fuse Block Details: Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Circuit Breaker > Component Information > Locations > Page 1752 Fuse Block Details: Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Technical Service Bulletins > Electrical - Aftermarket Fuse Warning Fuse: Technical Service Bulletins Electrical - Aftermarket Fuse Warning Bulletin No.: 07-08-45-002 Date: September 05, 2007 ADVANCED SERVICE INFORMATION Subject: Service Alert: Concerns With Aftermarket Fuses in GM Vehicles Models: 2008 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2008 and Prior HUMMER H2, H3 2008 and Prior Saab 9-7X Concerns with Harbor Freight Tools "Storehouse" Branded Blade Type Fuses General Motors has become aware of a fuse recall by Harbor Freight Tools/Storehouse for a variety of aftermarket fuses. In two cases, these fuses have not provided protection for the wiring system of the vehicles they were customer installed in. Upon testing the 15 amp version, it was found that the fuse still would not "open" when shorted directly across the battery terminals. How to Identify These Fuses Packed in a 120 piece set, the fuse has a translucent, hard plastic, blue body with the amperage stamped into the top. There are no white painted numbers on the fuse to indicate amperage. There are no identifying marks on the fuse to tell who is making it. The fuses are known to be distributed by Harbor Freight Tools but there may be other marketers, and packaging of this style of fuse. It would be prudent to replace these fuses if found in a customers vehicle. Likewise, if wiring overheating is found you should check the fuse panel for the presence of this style of fuse. All GM dealers should use genuine GM fuses on the vehicles they service. You should also encourage the use of GM fuses to your customers to assure they are getting the required electrical system protection. GM has no knowledge of any concerns with other aftermarket fuses. If additional information becomes available, this bulletin will be updated. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Locations > I/P Fuse Block LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Locations > I/P Fuse Block > Page 1759 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label Fuse: Application and ID Instrument Panel (I/P) Fuse Block Label I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 1762 I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 1763 Fuse: Application and ID Under Hood Electrical Center Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 1764 Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse > Component Information > Application and ID > Page 1765 I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) Fuse Block: Locations Auxiliary Fuse Block, Special Equipment Option (Seo) Under I/P Behind LH I/P, Left Of Brake Pedal Bracket Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 1770 Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 1771 LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 1772 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label Fuse Block: Application and ID Instrument Panel (I/P) Fuse Block Label I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 1775 I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 1776 Fuse Block: Application and ID Under Hood Electrical Center Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center Convenience Center: Locations Convenience Center LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 1781 Behind LH I/P, Left Of Brake Pedal Bracket LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 1782 Under I/P Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 1783 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Fuses and Circuit Breakers > Convenience Center <--> [Relay Box] > Component Information > Locations > Page 1784 Convenience Center: Application and ID Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Coolant Level Indicator Lamp > Component Information > Description and Operation Coolant Level Indicator Lamp: Description and Operation DESCRIPTION This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. OPERATION Some vehicles use a buzzer or indicator lamp to convey a low coolant level condition. The buzzer or lamp is activated by a sensor, located in the radiator, when the coolant level becomes one quart low, or more. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator Off W/Coolant Level Low Fig. 97 Chart 6: Low Coolant Level Indicator Inoperative W/Coolant Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low > Page 1791 Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator On w/Coolant Level OK Fig. 96 Chart 5: Low Coolant Level Indicator On W/Coolant Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Page 1792 Coolant Level Indicator Lamp: Service and Repair This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions Malfunction Indicator Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1797 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1798 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1799 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1800 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1801 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1802 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1803 Malfunction Indicator Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1804 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1805 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1806 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1807 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1808 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1809 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1810 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1811 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1812 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1813 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1814 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1815 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1816 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1817 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1818 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1819 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1820 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1821 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1822 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1823 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1824 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1825 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1826 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 1827 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Oil Change Reminder Lamp > Component Information > Service and Repair > Change Oil or Change Oil Now Message Oil Change Reminder Lamp: Service and Repair Change Oil or Change Oil Now Message 1. Turn ignition switch to On position, without starting engine. 2. Press accelerator pedal to wide open throttle (WOT) position and release three times within five seconds. 3. If Change Oil warning indicator goes out, system has been reset. 4. If Change Oil warning indicator does not reset, turn ignition switch Off and repeat procedure. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Oil Change Reminder Lamp > Component Information > Service and Repair > Change Oil or Change Oil Now Message > Page 1832 Oil Change Reminder Lamp: Service and Repair Engine Oil Life Monitor ENGINE OIL LIFE MONITOR The "CHANGE OIL" monitor light on the instrument cluster is a reminder to change oil. When changing oil, reset the oil life monitor whether the "CHANGE OIL" light came on or not. NOTE: Disconnecting the negative battery cable will not reset the oil life monitor. Reset monitor as follows: 1. Turn ignition switch to "ON" position, but don't start engine. 2. Fully depress accelerator pedal to Wide Open Throttle (WOT) position and release it three times within five seconds. ^ The light is controlled by the Powertrain Control Module (PCM). The PCM is monitoring the TPS signal for 3 consecutive signals above 96%. The PCM will acknowledge, if the reset was successful, by flashing the "Change Oil" light twice, then turning off the light. 3. If "CHANGE OIL" warning/indicator lamp flashes then goes out, the system has been reset. 4. If "CHANGE OIL" warning/indicator lamp doesn't reset, turn ignition switch "OFF" and repeat procedure. ^ If "CHANGE OIL" light is inoperative or remains "ON," refer to Powertrain Management / Computerized Engine Controls / Testing Procedures section. (DTC 95) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Oil Level Warning Indicator > Component Information > Description and Operation Oil Level Warning Indicator: Description and Operation DESCRIPTION This lamp illuminates to warn the driver that the engine oil level is low. When the ignition switch is first moved to Run, the oil level indicator lights for about 1 1/2 seconds as a bulb check. The oil level detection circuit has two internal timers. The first timer records the amount of time the ignition has been Off. The second timer records the amount of time the ignition has been On before the ignition was shut Off. The instrument cluster uses this information to determine if the engine has been sitting long enough for the oil to have returned to the oil pan. OPERATION The oil level monitoring circuits will check the oil level switch under the following conditions: 1. Ignition has been turned Off for more than 30 minutes. 2. Ignition has been Off for at least three minutes after ignition has been On for at least 12 minutes. If the oil level is low (oil level switch open), the "Check Oil" indicator will be turned On for the remainder of the ignition cycle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator Inoperative W/Oil Level Low Fig. 99 Chart 8: Low Oil Level Indicator Inoperative W/Oil Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Service Reminder Indicators > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low > Page 1838 Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator On w/Oil Level OK Fig. 98 Chart 7: Low Oil Level Indicator On W/Oil Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Vehicle Lifting > Component Information > Service and Repair Vehicle Lifting: Service and Repair Vehicle Lift Points Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires Tires: Technical Service Bulletins Wheels/Tires - Use of Nitrogen Gas in Tires INFORMATION Bulletin No.: 05-03-10-020C Date: April 27, 2010 Subject: Use of Nitrogen Gas in Tires Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 05-03-10-020B (Section 03 - Suspension). GM's Position on the Use of Nitrogen Gas in Tires General Motors does not oppose the use of purified nitrogen as an inflation gas for tires. We expect the theoretical benefits to be reduced in practical use due to the lack of an existing infrastructure to continuously facilitate inflating tires with nearly pure nitrogen. Even occasional inflation with compressed atmospheric air will negate many of the theoretical benefits. Given those theoretical benefits, practical limitations, and the robust design of GM original equipment TPC tires, the realized benefits to our customer of inflating their tires with purified nitrogen are expected to be minimal. The Promise of Nitrogen: Under Controlled Conditions Recently, nitrogen gas (for use in inflating tires) has become available to the general consumer through some retailers. The use of nitrogen gas to inflate tires is a technology used in automobile racing. The following benefits under controlled conditions are attributed to nitrogen gas and its unique properties: - A reduction in the expected loss of Tire Pressure over time. - A reduction in the variance of Tire Pressures with temperature changes due to reduction of water vapor concentration. - A reduction of long term rubber degradation due to a decrease in oxygen concentrations. Important These are obtainable performance improvements when relatively pure nitrogen gas is used to inflate tires under controlled conditions. The Promise of Nitrogen: Real World Use Nitrogen inflation can provide some benefit by reducing gas migration (pressure loss) at the molecular level through the tire structure. NHTSA (National Highway Traffic Safety Administration) has stated that the inflation pressure loss of tires can be up to 5% a month. Nitrogen molecules are larger than oxygen molecules and, therefore, are less prone to "seeping" through the tire casing. The actual obtainable benefits of nitrogen vary, based on the physical construction and the materials used in the manufacturing of the tire being inflated. Another potential benefit of nitrogen is the reduced oxidation of tire components. Research has demonstrated that oxygen consumed in the oxidation process of the tire primarily comes from the inflation media. Therefore, it is reasonable to assume that oxidation of tire components can be reduced if the tire is inflated with pure nitrogen. However, only very small amounts of oxygen are required to begin the normal oxidation process. Even slight contamination of the tire inflation gas with compressed atmospheric air during normal inflation pressure maintenance, may negate the benefits of using nitrogen. GM Tire Quality, Technology and Focus of Importance Since 1972, General Motors has designed tires under the TPC (Tire Performance Criteria) specification system, which includes specific requirements that ensure robust tire performance under normal usage. General Motors works with tire suppliers to design and manufacture original equipment tires for GM vehicles. The GM TPC addresses required performance with respect to both inflation pressure retention, and endurance properties for original equipment tires. The inflation pressure retention requirements address availability of oxygen and oxidation concerns, while endurance requirements ensure the mechanical structure of the tire has sufficient strength. This combination has provided our customers with tires that maintain their structural integrity throughout their useful treadlife under normal operating conditions. Regardless of the inflation media for tires (atmospheric air or nitrogen), inflation pressure maintenance of tires is critical for overall tire, and ultimately, vehicle performance. Maintaining the correct inflation pressure allows the tire to perform as intended by the vehicle manufacturer in many areas, including comfort, fuel economy, stopping distance, cornering, traction, treadwear, and noise. Since the load carrying capability of a tire is related to inflation pressure, proper inflation pressure maintenance is necessary for the tire to support the load imposed by the vehicle without excessive structural Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1847 degradation. Important Regardless of the inflation media for tires (atmospheric air or nitrogen), inflation pressure maintenance of tires is critical for overall tire, and ultimately, vehicle performance. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1848 Tires: Technical Service Bulletins Tires/Wheels - Tire Puncture Repair Procedures INFORMATION Bulletin No.: 04-03-10-001F Date: April 27, 2010 Subject: Tire Puncture Repair Procedures For All Cars and Light Duty Trucks Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 04-03-10-001E (Section 03 - Suspension). This bulletin covers puncture repair procedures for passenger car and light duty truck radial tires in the tread area only. The tire manufacturer must be contacted for its individual repair policy and whether or not the speed rating is retained after repair. Caution - Tire changing can be dangerous and should be done by trained professionals using proper tools and procedures. Always read and understand any manufacturer's warnings contained in their customers literature or molded into the tire sidewall. - Serious eye and ear injury may result from not wearing adequate eye and ear protection while repairing tires. - NEVER inflate beyond 275 kPa (40 pounds) pressure to seat beads. Some run flat tires, such as the Goodyear Extended Mobility Tire (EMT) used on the Corvette, may require more than 275 kPa (40 psi) to seat the bead. In such a case, a tire safety cage must be used. Consult the tire manufacturer for its individual repair policy. - NEVER stand, lean or reach over the assembly during inflation. Repairable area on a radial tire. Important - NEVER repair tires worn to the tread indicators 1.59 mm (2/32") remaining depth). - NEVER repair tires with a tread puncture larger than 6.35 mm (1/4"). - NEVER substitute an inner tube for a permissible or non-permissible repair. - NEVER perform an outside-in tire repair (plug only, on the wheel). - Every tire must be removed from the wheel for proper inspection and repair. - Regardless of the type of repair used, the repair must seal the inner liner and fill the injury. - Consult with repair material supplier/manufacturer for repair unit application procedures and repair tools/repair material recommendations. Three basic steps for tire puncture repair: 1. Remove the tire from the wheel for inspection and repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1849 2. Fill the injury (puncture) to keep moisture out. 3. Seal the inner liner with a repair unit to prevent air loss. External Inspection 1. Prior to demounting, inspect the tire surface, the valve and the wheel for the source of the leak by using a water and soap solution. Mark the injured area and totally deflate the tire by removing the valve core. 2. Demount the tire from the wheel and place the tire on a well-lighted spreader. Internal Inspection 1. Spread the beads and mark the puncture with a tire crayon. 2. Inspect the inner tire for any signs of internal damage. 3. Remove the puncturing object, noting the direction of the penetration. 4. Probe the injury with a blunt awl in order to determine the extent and direction of the injury. 5. Remove any loose foreign material from the injury. 6. Punctures exceeding 6.35 mm (1/4") should not be repaired. Cleaning 1. Clean the area around the puncture thoroughly with a proper liner cleaner, clean cloth and a scraper. This step serves to remove dirt and mold lubricants to insure proper adhesion and non-contamination of the buffing tool. 2. Refer to information on the product or manufacturer's Material Safety Data Sheet and follow guidelines for handling and disposal. Clean the Injury Channel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1850 1. Use a proper hand reamer, carbide cutter or drill bit to ream the puncture channel from the inside of the tire in order to clean the injury. 2. Remove steel wires protruding above the liner surface to prevent damage to the repair unit. 3. Consult your repair material supplier for recommended reaming tool(s). Fill the Injury 1. It is necessary to fill the injury channel to provide back up for the repair unit and to prevent moisture from entering the tire fabric and steel wires. 2. (For combination repair/plug units skip this step.) Cement the injured channel and fill the injury from the inside of the tire with the repair plug per repair material manufacturer's recommendations. Without stretching the plug, cut the plug off just above the inside tire surface. 3. Consult your repair material supplier for proper repair material selection. Repair Unit Selection Important Do not install the repair unit in this step. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1851 1. Center the repair unit over the injury as a reference and outline an area larger than the unit so that buffing will not remove the crayon marks. 2. Remove the repair unit. 3. DO NOT overlap previous or multiple repair units. 4. Consult your repair material supplier for proper repair unit selection. Buffing 1. To prevent contamination and preserve the outline, buff within the marked area thoroughly and evenly with a low speed buffing tool using a fine wire brush or gritted rasp. 2. Buff to a smooth velvet surface (RMA #1 or #2 buffed texture). 3. Use caution not to gouge the inner liner or expose casing fabric. 4. Remove any buffing dust with a vacuum cleaner. 5. Consult your repair material supplier for a proper buffing tool. Cementing Apply chemical cement according to the repair material manufacturer's procedures. Repair Unit Application Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1852 1. The tire must be in the relaxed position when the repair unit is installed (Do not spread the beads excessively). Two-Piece Plug and Repair Units 1. If applicable, install the repair unit so that the alignment is correct. 2. Center the repair unit over the injury and stitch down thoroughly with the stitching tool, working from the center out. 3. Being careful not to stretch the plug material, cut the plug flush with the outer tread. Combination Repair/Plug Units 1. Pull the plug through the injury until the repair just reaches the liner. Stitch down thoroughly. 2. Follow the repair material manufacturer's recommendations for further installation instructions. 2. Consult your repair material supplier for the proper stitching tool. Safety Cage Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1853 Some run flat tires, such as the Goodyear Extended Mobility Tire (EMT) used on the Corvette, may require more than 275 kPa (40 psi) to seat the bead. In such a case, a tire safety cage must be used. Consult the tire manufacturer for its individual repair policy. Final Inspection 1. After remounting and inflating the tire, check both beads, the repair and the valve with a water and soap solution in order to detect leaks. 2. If the tire continues to lose air, the tire must be demounted and reinspected. 3. Balance the tire and wheel assembly. Refer to Tire and Wheel Assembly Balancing - OFF Vehicle. For additional tire puncture repair information, contact: Rubber Manufacturers Association (RMA) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1854 Tires: Technical Service Bulletins Tires - Correct Inflation Pressure Information INFORMATION Bulletin No.: 00-00-90-002J Date: January 28, 2009 Subject: Information on Proper Tire Pressure Models: 2010 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2009 and Prior HUMMER H2, H3, H3T 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add model years and clarify additional information. Please discard Corporate Bulletin Number 00-00-90-002I (Section 00 - General Information). Important: ^ Adjustment of tire pressure for a customer with a Low Tire Pressure Monitor (TPM) light on and no codes in the TPM system is NOT a warrantable repair. Claims to simply adjust the tire pressure will be rejected. ^ ALL tires (including the spare tire) MUST be set to the recommended inflation pressure stated on the vehicle's tire placard (on driver's door) during the PRE-DELIVERY INSPECTION (PDI). Recommended inflation pressure is not the pressure printed on tire sidewall. ^ Tires may be over-inflated from the assembly plant due to the mounting process. ^ Generally a 5.6°C (10°F) temperature change will result in (is equivalent to) a 6.9 kPa (1 psi) tire pressure change. ^ 2008-2009 HUMMER H2 Only - The H2 comes standard with Light Truck "D" Load Range tires with a recommended cold inflation pressure of 289 kPa (42 psi). These tires will alert the driver to a low pressure situation at roughly 262 kPa (38 psi) due to a requirement in FMVSS 138 which specifies a Minimum Activation Pressure for each tire type. This creates a relatively narrow window of "usable" pressure values and the warning will be more sensitive to outside temperature changes during the colder months. As with other cold temperature/tire pressure issues, there is nothing wrong with the system itself. If a vehicle is brought in with this concern, check for tire damage and set all tires to the Recommended Cold Inflation Pressure shown on the vehicle placard. Accurate tire pressures ensure the safe handling and appropriate ride characteristics of GM cars and trucks. It is critical that the tire pressure be adjusted to the specifications on the vehicle¡C■s tire placard during PDI. Ride, handling and road noise concerns may be caused by improperly adjusted tire pressure. The first step in the diagnosis of these concerns is to verify that the tires are inflated to the correct pressures. The recommended tire inflation pressure is listed on the vehicle¡C■s tire placard. The tire placard is located on the driver¡C■s side front or rear door edge, center pillar, or the rear compartment lid. Tip ^ Generally a 5.6°C (10°F) temperature increase will result in (is equivalent to) a 6.9 kPa (1 psi) tire pressure increase. ^ The definition of a "cold" tire is one that has been sitting for at least 3 hours, or driven no more than 1.6 km (1 mi). ^ On extremely cold days, if the vehicle has been indoors, it may be necessary to compensate for the low external temperature by adding additional air to the tire during PDI. ^ During cold weather, the Tire Pressure Monitor (TPM) indicator light (a yellow horseshoe with an exclamation point) may illuminate. If this indicator turns off after the tires warm up (reach operating temperature), the tire pressure should be reset to placard pressure at the cold temperature. ^ The TPM system will work correctly with nitrogen in tires. ^ The TPM system is compatible with the GM Vehicle Care Tire Sealant but may not be with other commercially available sealants. Important: ^ Do not use the tire pressure indicated on the tire itself as a guide. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 1855 ^ Always inspect and adjust the pressure when the tires are cold. ^ Vehicles that have different pressures for the front and the rear need to be adjusted after tire rotation. Improper tire inflation may result in any or all of the following conditions: ^ Premature tire wear ^ Harsh ride ^ Excessive road noise ^ Poor handling ^ Reduced fuel economy ^ Low Tire Pressure Monitor (TPM) Light ON ^ Low Tire Pressure Message on the Drivers Information Center (DIC) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Page 1856 Tires: Specifications Front .................................................................................................................................................... ......................................................... 210 kPa (30 psi) Rear ................................................................ .............................................................................................................................................. 210 kPa (30 psi) Full-Size Spare ....................................................................................................................... ...................................................................... 240 kPa (35 psi) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) Wheels: Customer Interest Wheels/Tires - Tire Radial Force Variation (RFV) INFORMATION Bulletin No.: 00-03-10-006F Date: May 04, 2010 Subject: Information on Tire Radial Force Variation (RFV) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X 2000-2005 Saturn L Series 2003-2007 Saturn ION Supercede: This bulletin is being revised to considerably expand the available information on Radial Force Variation (RFV) and should be reviewed in whole. Please discard Corporate Bulletin Number 00-03-10-006E (Section 03 - Suspension). Important - Before measuring tires on equipment such as the Hunter GSP9700, the vehicle MUST be driven a minimum of 16 km (10 mi) to ensure removal of any flat-spotting. Refer to Corporate Bulletin Number 03-03-10-007E - Tire/Wheel Characteristics of GM Original Equipment Tires. - Equipment such as the Hunter GSP9700 MUST be calibrated prior to measuring tire/wheel assemblies for each vehicle. The purpose of this bulletin is to provide guidance to GM dealers when using tire force variation measurement equipment, such as the Hunter GSP9700. This type of equipment can be a valuable tool in diagnosing vehicle ride concerns. The most common ride concern involving tire radial force variation is highway speed shake on smooth roads. Tire related smooth road highway speed shake can be caused by three conditions: imbalance, out of round and tire force variation. These three conditions are not necessarily related. All three conditions must be addressed. Imbalance is normally addressed first, because it is the simpler of the three to correct. Off-vehicle, two plane dynamic wheel balancers are readily available and can accurately correct any imbalance. Balancer calibration and maintenance, proper attachment of the wheel to the balancer, and proper balance weights, are all factors required for a quality balance. However, a perfectly balanced tire/wheel assembly can still be "oval shaped" and cause a vibration. Before balancing, perform the following procedures. Tire and Wheel Diagnosis 1. Set the tire pressure to the placard values. 2. With the vehicle raised, ensure the wheels are centered on the hub by loosening all wheel nuts and hand-tightening all nuts first by hand while shaking the wheel, then torque to specifications using a torque wrench, NOT a torque stick. 3. Visually inspect the tires and the wheels. Inspect for evidence of the following conditions and correct as necessary: - Missing balance weights - Bent rim flange - Irregular tire wear - Incomplete bead seating - Tire irregularities (including pressure settings) - Mud/ice build-up in wheel - Stones in the tire tread - Remove any aftermarket wheels and/or tires and restore vehicle to original condition prior to diagnosing a smooth road shake condition. 4. Road test the vehicle using the Electronic Vibration Analyzer (EVA) essential tool. Drive for a sufficient distance on a known, smooth road surface to duplicate the condition. Determine if the vehicle is sensitive to brake apply. If the brakes are applied lightly and the pulsation felt in the steering wheel increases, refer to the Brakes section of the service manual that deals with brake-induced pulsation. If you can start to hear the vibration as a low boom noise (in addition to feeling it), but cannot see it, the vehicle likely has a first order (one pulse per propshaft revolution) driveline vibration. Driveline first order vibrations are high enough in frequency that most humans can start to hear them at highway speeds, but are too high to be able to be easily seen. These issues can be caused by driveline imbalance or misalignment. If the vehicle exhibits this low boom and the booming pulses in-and-out on a regular basis (like a throbbing), chances are good that the vehicle could have driveline vibration. This type Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 1865 of vibration is normally felt more in the "seat of the pants" than the steering wheel. 5. Next, record the Hertz (Hz) reading as displayed by the EVA onto the tire data worksheet found at the end of this bulletin. This should be done after a tire break-in period of at least 16 km (10 mi) at 72 km/h (45 mph) or greater, in order to eliminate any possible tire flat-spotting. This reading confirms what the vehicle vibration frequency is prior to vehicle service and documents the amount of improvement occurring as the result of the various steps taken to repair. Completing the Steering Wheel Shake Worksheet below is required. A copy of the completed worksheet must be saved with the R.O. and a copy included with any parts returned to the Warranty Parts Center for analysis. A reading of 35 to 50 Hz typically indicates a first order propshaft vibration. If this is the situation, refer to Corporate Bulletin Number 08-07-30-044D. Generally, a reading between 10 and 20 Hz indicates a tire/wheel vibration and if this is the reading obtained, continue using this bulletin. If the tire 1st order vibration goes away and stays away during this evaluation, the cause is likely tire flat-spotting. Tire flat-spotting vibration may come and go at any speed over 72 km/h (45 mph) during the first 10 minutes of operation, if vibration continues after 10 minutes of driving at speeds greater than 72 km/h (45 mph), tire flat-spotting can be ruled out as the cause for vibration. 6. If flat-spotting is the cause, provide the explanation that this has occurred due to the vehicle being parked for long periods of time and that the nature of the tire is to take a set. Refer to Corporate Bulletin Number 03-03-10-007E: Information on Tire/Wheel Characteristics (Vibration, Balance, Shake, Flat Spotting) of GM Original Equipment Tires. 7. If the road test indicates a shake/vibration exists, check the imbalance of each tire/wheel assembly on a known, calibrated, off-car dynamic balancer.Make sure the mounting surface of the wheel and the surface of the balancer are absolutely clean and free of debris. Be sure to chose the proper cone/collet for the wheel, and always use the pilot bore for centering. Never center the wheel using the hub-cap bore since it is not a precision machined surface. If any assembly calls for more than 1/4 ounce on either rim flange, remove all balance weights and rebalance to as close to zero as possible. If you can see the vibration (along with feeling it) in the steering wheel (driving straight without your hands on the wheel), it is very likely to be a tire/wheel first order (one pulse per revolution) disturbance. First order disturbances can be caused by imbalance as well as non-uniformities in tires, wheels or hubs. This first order frequency is too low for a human to hear, but if the amplitude is high enough, it can be seen. If a vibration or shake still exists after balancing, any out of round conditions, of the wheel, and force variation conditions of the tire, must be addressed. Equipment such as the Hunter GSP9700 can address both (it is also a wheel balancer). Tire radial force vibration (RFV) can be defined as the amount of stiffness variation the tire will produce in one revolution under a constant load. Radial force variation is what the vehicle feels because the load (weight) of the vehicle is always on the tires. Although free runout of tires (not under load) is not always a good indicator of a smooth ride, it is critical that total tire/wheel assembly runout be within specification. Equipment such as the Hunter GSP9700 loads the tire, similar to on the vehicle, and measures radial force variation of the tire/wheel assembly. Note that the wheel is affecting the tire's RFV measurement at this point. To isolate the wheel, its runout must be measured. This can be easily done on the Hunter, without the need to set up dial indicators. If the wheel meets the runout specification, the tire's RFV can then be addressed. After measuring the tire/wheel assembly under load, and the wheel alone, the machine then calculates (predicts) the radial force variation of the tire. However, because this is a prediction that can include mounting inaccuracies, and the load wheel is much smaller in diameter than used in tire production, this type of service equipment should NOT be used to audit new tires. Rather, it should be used as a service diagnostic tool to minimize radial force variation of the tire/wheel assembly. Equipment such as the Hunter GSP9700 does an excellent job of measuring wheel runout, and of finding the low point of the wheel (for runout) and the high point of the tire (for radial force variation). This allows the tire to be matched mounted to the wheel for lowest tire/wheel assembly force variation. The machine will simplify this process into easy steps. The following assembly radial force variation numbers should be used as a guide: When measuring RFV and match mounting tires perform the following steps. Measuring Wheel Runout and Assembly Radial Force Variation Important The completed worksheet at the end of this bulletin must be attached to the hard copy of the repair order. - Measure radial force variation and radial runout. - If a road force/balancing machine is used, record the radial force variation (RFV) on the worksheet at the end of this bulletin. It may be of benefit to have the lowest RFV assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires onto the subject vehicle. - If a runout/balancing machine is used, record the radial runout of the tire/wheel assemblies on the worksheet at the end of this bulletin. If one or more of the tire/wheel assemblies are more than.040 in (1.02 mm), match mount the tire to the wheel to get below.040 in (1.02 mm). For sensitive customers, readings of 0.030 inch (0.76 mm) or less are preferable, it may also be of benefit to have the lowest runout assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 1866 onto the subject vehicle. - After match mounting, the tire/wheel assembly must be rebalanced. If match mounting tires to in-spec wheels produces assembly values higher than these, tire replacement may be necessary. Replacing tires at lower values will probably mean good tires are being condemned. Because tires can sometimes become temporarily flat-spotted, which will affect force variation, it is important that the vehicle be driven at least 16 km (10 mi) prior to measuring. Tire pressure must also be adjusted to the usage pressure on the vehicle's tire placard prior to measuring. Most GM vehicles will tolerate radial force variation up to these levels. However, some vehicles are more sensitive, and may require lower levels. Also, there are other tire parameters that equipment such as the Hunter GSP9700 cannot measure that may be a factor. In such cases, TAC should be contacted for further instructions. Important - When mounting a GM wheel to a wheel balancer/force variation machine, always use the wheel's center pilot hole. This is the primary centering mechanism on all GM wheels; the bolt holes are secondary. Usually a back cone method to the machine should be used. For added accuracy and repeatability, a flange plate should be used to clamp the wheel onto the cone and machine. This system is offered by all balancer manufacturers in GM's dealer program. - Any type of service equipment that removes tread rubber by grinding, buffing or truing is NOT recommended, and may void the tire warranty. However, tires may have been ground by the tire company as part of their tire manufacturing process. This is a legitimate procedure. Steering Wheel Shake Worksheet When diagnosing vibration concerns, use the following worksheet in conjunction with the appropriate Vibration Analysis-Road testing procedure in the Vibration Correction sub-section in SI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 1867 Refer to the appropriate section of SI for specifications and repair procedures that are related to the vibration concern. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels Wheels: Customer Interest Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels TECHNICAL Bulletin No.: 05-03-10-003F Date: April 27, 2010 Subject: Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X with Cast Aluminum Wheels Supercede: This bulletin is being revised to update the model years and the bulletin reference information. Please discard Corporate Bulletin Number 05-03-10-003E (Section 03 - Suspension). Condition Some customers may comment on a low tire pressure condition. Diagnosis of the low tire pressure condition indicates an air leak through the cast aluminum wheel. Cause Porosity in the cast aluminum wheel may be the cause. Notice This bulletin specifically addresses issues related to the wheel casting that may result in an air leak. For issues related to corrosion of the wheel in service, please refer to Corporate Bulletin Number 08-03-10-006C - Tire Slowly Goes Flat, Tire Air Loss, Low Tire Pressure Warning Light Illuminated, Aluminum Wheel Bead Seat Corrosion (Clean and Resurface Wheel Bead Seat). Correction 1. Remove the tire and wheel assembly from the vehicle. Refer to the appropriate service procedure in SI. 2. Locate the leaking area by inflating the tire to 276 kPa (40 psi) and dipping the tire/wheel assembly in a water bath, or use a spray bottle with soap and water to locate the specific leak location. Important - If the porosity leak is located in the bead area of the aluminum rim (where the tire meets the rim), the wheel should be replaced. - If two or more leaks are located on one wheel, the wheel should be replaced. 3. If air bubbles are observed, mark the location. - If the leak location is on the tire/rubber area, refer to Corporate Bulletin Number 04-03-10-001F Tire Puncture Repair Procedures for All Cars and Light Duty Trucks. - If the leak is located on the aluminum wheel area, continue with the next step. 4. Inscribe a mark on the tire at the valve stem in order to indicate the orientation of the tire to the wheel. 5. Dismount the tire from the wheel. Refer to Tire Mounting and Dismounting. 6. Remove the tire pressure sensor. Refer to Tire Pressure Sensor removal procedure in SI. 7. Scuff the INSIDE rim surface at the leak area with #80 grit paper and clean the area with general purpose cleaner, such as 3M(R) General Purpose Adhesive Cleaner, P/N 08984, or equivalent. 8. Apply a 3 mm (0.12 in) thick layer of Silicone - Adhesive/Sealant, P/N 12378478 (in Canada, use 88900041), or equivalent, to the leak area. 9. Allow for the adhesive/sealant to dry. Notice Caution must be used when mounting the tire so as not to damage the sealer. Damaging the repair area may result in an air leak. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels > Page 1872 10. Align the inscribed mark on the tire with the valve stem on the wheel. 11. Reinstall the Tire Pressure Sensor. Refer to Tire Pressure Sensor installation procedure in SI. 12. Mount the tire on the wheel. Refer to Tire Mounting and Dismounting. 13. Pressurize the tire to 276 kPa (40 psi) and inspect for leaks. 14. Adjust tire pressure to meet the placard specification. 15. Balance the tire/wheel assembly. Refer to Tire and Wheel Assembly Balancing - Off-Vehicle. 16. Install the tire and wheel assembly onto the vehicle. Refer to the appropriate service procedure in SI. Parts Information Warranty Information (excluding Saab U.S. Models) Important The Silicone - Adhesive/Sealant comes in a case quantity of six. ONLY charge warranty one tube of adhesive/sealant per wheel repair. For vehicles repaired under warranty, use: One leak repair per wheel. Warranty Information (Saab U.S. Models) For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Staining/Pitting/Corrosion INFORMATION Bulletin No.: 00-03-10-002F Date: April 21, 2011 Subject: Chemical Staining, Pitting, Corrosion and/or Spotted Appearance of Chromed Aluminum Wheels Models: 2012 and Prior GM Cars and Trucks Supercede: This bulletin is being revised to update model years, suggest additional restorative products and add additional corrosion information. Please discard Corporate Bulletin Number 00-03-10-002E (Section 03 - Suspension). Important You may give a copy of this bulletin to the customer. What is Chemical Staining of Chrome Wheels? Figure 1 Chemical staining in most cases results from acid based cleaners (refer to Figure 1 for an example). These stains are frequently milky, black, or greenish in appearance. They result from using cleaning solutions that contain acids on chrome wheels. Soap and water is usually sufficient to clean wheels. If the customer insists on using a wheel cleaner they should only use one that specifically states that it is safe for chromed wheels and does not contain anything in the following list. (Dealers should also survey any products they use during prep or normal cleaning of stock units for these chemicals.) - Ammonium Bifluoride (fluoride source for dissolution of chrome) - Hydrofluoric Acid (directly dissolves chrome) - Hydrochloric Acid (directly dissolves chrome) - Sodium Dodecylbenzenesulfonic Acid - Sulfamic Acid - Phosphoric Acid - Hydroxyacetic Acid Notice Many wheel cleaner instructions advise to take care to avoid contact with painted surfaces. Most customers think of painted surfaces as the fenders, quarter panels and other exterior sheet metal. Many vehicles have painted brake calipers. Acidic wheel cleaners may craze, crack, or discolor the paint on the brake calipers. Damage from wheel cleaners is not covered under the vehicle new car warranty. Soap and water applied with a soft brush is usually all that is required to clean the calipers. Whenever any wheel cleaner is used, it must be THOROUGHLY rinsed off of the wheel with clean, clear water. Special care must be taken to rinse under the hub cap, balance weights, wheel nuts, lug nut caps, between the wheel cladding and off the back side of the wheel. Wheels returned to the Warranty Parts Center (WPC) that exhibit damage from wheel cleaners most often have the damage around and under the wheel weight where the cleaner was incompletely flushed away. Notice Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 1878 Do not use cleaning solutions that contain hydrofluoric, oxalic and most other acids on chrome wheels (or any wheels). If the customer is unsure of the chemical make-up of a particular wheel cleaner, it should be avoided. For wheels showing signs of milky staining from acidic cleaners, refer to Customer Assistance and Instructions below. Warranty of Stained Chrome Wheels Stained wheels are not warrantable. Most acid based cleaners will permanently stain chrome wheels. Follow-up with dealers has confirmed that such cleaners were used on wheels that were returned to the Warranty Parts Center (WPC). Any stained wheels received by the WPC will be charged back to the dealership. To assist the customer, refer to Customer Assistance and Instructions below. Pitting or Spotted Appearance of Chrome Wheels Figure 2 A second type or staining or finish disturbance may result from road chemicals, such as calcium chloride used for dust control of unpaved roads. The staining will look like small pitting (refer to Figure 2). This staining will usually be on the leading edges of each wheel spoke, but may be uniformly distributed. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Important Road chemicals, such as calcium chloride used for dust control of unpaved roads, can also stain chrome wheels. The staining will look like small pitting. This staining will usually be on the leading edges of each wheel spoke. This is explained by the vehicle traveling in the forward direction while being splashed by the road chemical. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Warranty of Pitted or Spotted Chrome Wheels Wheels returned with pitting or spotting as a result of road chemicals may be replaced one time. Damage resulting from contact with these applied road chemicals is corrosive to the wheels finish and may cause damage if the wheels are not kept clean. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean if they are operating the vehicle in an area that applies calcium chloride or other dust controlling chemicals! "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). "Stardust" Corrosion of Chrome Wheels Figure 3 A third type of finish disturbance results from prolonged exposure to brake dust and resultant penetration of brake dust through the chrome. As brakes are applied hot particles of brake material are thrown off and tend to be forced through the leading edge of the wheel spoke windows by airflow. These Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 1879 hot particles embed themselves in the chrome layer and create a small pit. If the material is allowed to sit on the wheel while it is exposed to moisture or salt, it will corrode the wheel beneath the chrome leaving a pit or small blister in the chrome. Heavy brake dust build-up should be removed from wheels by using GM Chrome Cleaner and Polish, P/N 1050173 (in Canada use 10953013). For moderate cleaning, light brake dust build-up or water spots use GM Swirl Remover Polish, P/N 12377965 (in Canada, use Meguiars Plast-X(TM) Clear Plastic Cleaner and Polish #G12310C**). After cleaning, the wheel should be waxed using GM Cleaner Wax, P/N 12377966 (in Canada, use Meguiars Cleaner Wax #M0616C**), which will help protect the wheel from brake dust and reduce adhesion of any brake dust that gets on the wheel surface. For general maintenance cleaning, PEEK Metal Polish† may be used. It will clean and shine the chrome and leave behind a wax coating that may help protect the finish. Warranty of Stardust Corroded Chrome Wheels Wheels returned with pitting or spotting as a result of neglect and brake dust build-up may be replaced one time. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean and free of prolonged exposure to brake dust build-up. "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). Customer Assistance and Instructions GM has looked for ways customers may improve the appearance of wheels damaged by acidic cleaners. The following product and procedure has been found to dramatically improve the appearance of stained wheels. For wheels that have milky stains caused by acidic cleaners try the following: Notice THE 3M CHROME AND METAL POLISH REQUIRED FOR THIS PROCEDURE IS AN EXTREMELY AGGRESSIVE POLISH/CLEANER. THE WHEELS MUST BE CLEANED BEFORE APPLICATION TO AVOID SCRATCHING THE WHEEL SURFACE. THIS PRODUCT WILL REDUCE THE THICKNESS OF THE CHROME PLATING ON THE WHEEL AND IF USED INCORRECTLY OR EXCESSIVELY MAY REMOVE THE CHROME PLATING ALL TOGETHER, EXPOSING A LESS BRIGHT AND BRASSY COLORED SUB-LAYER. FOLLOW INSTRUCTIONS EXACTLY. 1. Wash the wheels with vigorously with soap and water. This step will clean and may reduce wheel staining. Flood all areas of the wheel with water to rinse. 2. Dry the wheels completely. Notice Begin with a small section of the wheel and with light pressure buff off polish and examine results. ONLY apply and rub with sufficient force and time to remove enough staining that you are satisfied with the results. Some wheels may be stained to the extent that you may only achieve a 50% improvement while others may be able to be restored to the original lustre. IN ALL CASES, only apply until the results are satisfactory. 3. Apply 3M Chrome and Metal Polish #39527* with a clean terry cloth towel. As you apply the polish, the staining will be diminished. 4. When dry, buff off the polish with a clean portion of the towel. 5. Repeat application of the 3M Chrome and Metal Polish until satisfied with the results. If continued applications fail to improve the appearance further discontinue use. This procedure will improve the appearance of the wheels and may, with repeated applications, restore the finish dramatically. For wheels that exhibit spotting from road chemicals the above procedure may marginally improve the condition but will not restore the finish or remove the pitting. In this type of staining the wheel finish has actually been removed in spots and no manner of cleaning will restore the finish. †*We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Parts Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 1880 *This product is currently available from 3M. To obtain information for your local retail location please call 3M at 1-888-364-3577. **This product is currently available from Meguiars (Canada). To obtain information for your local retail location please call Meguiars at 1-800-347-5700 or at www.meguiarscanada.com. ^ This product is currently available from Tri-Peek International. To obtain information for your local retail location please call Tri-Peek at 1-877-615-4272 or at www.tripeek.com. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires - Refinishing Aluminum Wheels Wheels: All Technical Service Bulletins Wheels/Tires - Refinishing Aluminum Wheels INFORMATION Bulletin No.: 99-08-51-007E Date: March 17, 2011 Subject: Refinishing Aluminum Wheels Models: 2012 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 99-08-51-007D (Section 08 - Body and Accessories). This bulletin updates General Motor's position on refinishing aluminum wheels. GM does not endorse any repairs that involve welding, bending, straightening or re-machining. Only cosmetic refinishing of the wheel's coatings, using recommended procedures, is allowed. Evaluating Damage In evaluating damage, it is the GM Dealer's responsibility to inspect the wheel for corrosion, scrapes, gouges, etc. The Dealer must insure that such damage is not deeper than what can be sanded or polished off. The wheel must be inspected for cracks. If cracks are found, discard the wheel. Any wheels with bent rim flanges must not be repaired or refinished. Wheels that have been refinished by an outside company must be returned to the same vehicle. The Dealer must record the wheel ID stamp or the cast date on the wheel in order to assure this requirement. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. Aluminum Wheel Refinishing Recommendations - Chrome-plated aluminum wheels Re-plating these wheels is not recommended. - Polished aluminum wheels These wheels have a polyester or acrylic clearcoat on them. If the clearcoat is damaged, refinishing is possible. However, the required refinishing process cannot be performed in the dealer environment. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. - Painted aluminum wheels These wheels are painted using a primer, color coat, and clearcoat procedure. If the paint is damaged, refinishing is possible. As with polished wheels, all original coatings must be removed first. Media blasting is recommended. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for the re-painting of this type of wheel. - Bright, machined aluminum wheels These wheels have a polyester or acrylic clearcoat on them. In some cases, the recessed "pocket" areas of the wheel may be painted. Surface refinishing is possible. The wheel must be totally stripped by media blasting or other suitable means. The wheel should be resurfaced by using a sanding process rather than a machining process. This allows the least amount of material to be removed. Important Do not use any re-machining process that removes aluminum. This could affect the dimensions and function of the wheel. Painting is an option to re-clearcoating polished and bright machined aluminum wheels. Paint will better mask any surface imperfections and is somewhat more durable than clearcoat alone. GM recommends using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option, the body color may also be used. When using any of the painting options, it is recommended that all four wheels be refinished in order to maintain color uniformity. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for specific procedures and product recommendations. Refinisher's Responsibility - Outside Company Important Some outside companies are offering wheel refinishing services. Such refinished wheels will be permanently marked by the refinisher and are warranted by the refinisher. Any process that re-machines or otherwise re-manufactures the wheel should not be used. A refinisher's responsibility includes inspecting for cracks using the Zyglo system or the equivalent. Any cracked wheels must not be refinished. No welding, hammering or reforming of any kind is allowed. The wheel ID must be recorded and follow the wheel throughout the process in order to assure that the same wheel is returned. A plastic media blast may be used for clean up of the wheel. Hand and/or lathe sanding of the machined surface and the wheel window is allowed. Material removal, though, must be kept to a minimum. Re-machining of the wheel is not allowed. Paint and/or clear coat must not be present on the following surfaces: the nut chamfers, the wheel mounting surfaces and the wheel pilot hole. The refinisher must permanently ID stamp the wheel and warrant the painted/clearcoated surfaces for a minimum of one year or the remainder of the new vehicle warranty, whichever is Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires - Refinishing Aluminum Wheels > Page 1885 longer. Important Whenever a wheel is refinished, the mounting surface and the wheel nut contact surfaces must not be painted or clearcoated. Coating these surfaces could affect the wheel nut torque. When re-mounting a tire on an aluminum wheel, coated balance weights must be used in order to reduce the chance of future cosmetic damage. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions Wheels: All Technical Service Bulletins Wheels - Changing Procedures/Precautions INFORMATION Bulletin No.: 06-03-10-010A Date: June 09, 2010 Subject: Information on Proper Wheel Changing Procedures and Cautions Models: 2011 and Prior GM Passenger Cars and Trucks 2010 and Prior HUMMER Models 2005-2009 Saab 9-7X 2005-2009 Saturn Vehicles Attention: Complete wheel changing instructions for each vehicle line can be found under Tire and Wheel Removal and Installation in Service Information (SI). This bulletin is intended to quickly review and reinforce simple but vital procedures to reduce the possibility of achieving low torque during wheel installation. Always refer to SI for wheel lug nut torque specifications and complete jacking instructions for safe wheel changing. Supercede: This bulletin is being revised to include the 2011 model year and update the available special tool list. Please discard Corporate Bulletin Number 06-03-10-010 (Section 03 Suspension). Frequency of Wheel Changes - Marketplace Driven Just a few years ago, the increasing longevity of tires along with greater resistance to punctures had greatly reduced the number of times wheels were removed to basically required tire rotation intervals. Today with the booming business in accessory wheels/special application tires (such as winter tires), consumers are having tire/wheel assemblies removed - replaced - or installed more than ever. With this increased activity, it opens up more of a chance for error on the part of the technician. This bulletin will review a few of the common concerns and mistakes to make yourself aware of. Proper Servicing Starts With the Right Tools The following tools have been made available to assist in proper wheel and tire removal and installation. - J 41013 Rotor Resurfacing Kit (or equivalent) - J 42450-A Wheel Hub Resurfacing Kit (or equivalent) Corroded Surfaces One area of concern is corrosion on the mating surfaces of the wheel to the hub on the vehicle. Excessive corrosion, dirt, rust or debris built up on these surfaces can mimic a properly tightened wheel in the service stall. Once the vehicle is driven, the debris may loosen, grind up or be washed away from water splash. This action may result in clearance at the mating surface of the wheel and an under-torqued condition. Caution Before installing a wheel, remove any buildup on the wheel mounting surface and brake drum or brake disc mounting surface. Installing wheels with poor metal-to-metal contact at the mounting surfaces can cause wheel nuts to loosen. This may cause a wheel to come off when the vehicle is moving, possibly resulting in a loss of control or personal injury. Whenever you remove the tire/wheel assemblies, you must inspect the mating surfaces. If corrosion is found, you should remove the debris with a die grinder equipped with a fine sanding pad, wire brush or cleaning disc. Just remove enough material to assure a clean, smooth mating surface. The J 41013 (or equivalent) can be used to clean the following surfaces: - The hub mounting surface - The brake rotor mounting surface - The wheel mounting surface Use the J 42450-A (or equivalent) to clean around the base of the studs and the hub. Lubricants, Grease and Fluids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 1890 Some customers may use penetrating oils, grease or other lubricants on wheel studs to aid in removal or installation. Always use a suitable cleaner/solvent to remove these lubricants prior to installing the wheel and tire assemblies. Lubricants left on the wheel studs may cause improper readings of wheel nut torque. Always install wheels to clean, dry wheel studs ONLY. Notice Lubricants left on the wheel studs or vertical mounting surfaces between the wheel and the rotor or drum may cause the wheel to work itself loose after the vehicle is driven. Always install wheels to clean, dry wheel studs and surfaces ONLY. Beginning with 2011 model year vehicles, put a light coating of grease, GM P/N 1051344 (in Canada, P/N 9930370), on the inner surface of the wheel pilot hole to prevent wheel seizure to the axle or bearing hub. Wheel Stud and Lug Nut Damage Always inspect the wheel studs and lug nuts for signs of damage from crossthreading or abuse. You should never have to force wheel nuts down the stud. Lug nuts that are damaged may not retain properly, yet give the impression of fully tightening. Always inspect and replace any component suspected of damage. Tip Always start wheel nuts by hand! Be certain that all wheel nut threads have been engaged BEFORE tightening the nut. Important If the vehicle has directional tread tires, verify the directional arrow on the outboard side of the tire is pointing in the direction of forward rotation. Wheel Nut Tightening and Torque Improper wheel nut tightening can lead to brake pulsation and rotor damage. In order to avoid additional brake repairs, evenly tighten the wheel nuts to the proper torque specification as shown for each vehicle in SI. Always observe the proper wheel nut tightening sequence as shown below in order to avoid trapping the wheel on the wheel stud threads or clamping the wheel slightly off center resulting in vibration. The Most Important Service You Provide While the above information is well known, and wheel removal so common, technicians run the risk of becoming complacent on this very important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 1891 service operation. A simple distraction or time constraint that rushes the job may result in personal injury if the greatest of care is not exercised. Make it a habit to double check your work and to always side with caution when installing wheels. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) Wheels: All Technical Service Bulletins Wheels/Tires - Tire Radial Force Variation (RFV) INFORMATION Bulletin No.: 00-03-10-006F Date: May 04, 2010 Subject: Information on Tire Radial Force Variation (RFV) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X 2000-2005 Saturn L Series 2003-2007 Saturn ION Supercede: This bulletin is being revised to considerably expand the available information on Radial Force Variation (RFV) and should be reviewed in whole. Please discard Corporate Bulletin Number 00-03-10-006E (Section 03 - Suspension). Important - Before measuring tires on equipment such as the Hunter GSP9700, the vehicle MUST be driven a minimum of 16 km (10 mi) to ensure removal of any flat-spotting. Refer to Corporate Bulletin Number 03-03-10-007E - Tire/Wheel Characteristics of GM Original Equipment Tires. - Equipment such as the Hunter GSP9700 MUST be calibrated prior to measuring tire/wheel assemblies for each vehicle. The purpose of this bulletin is to provide guidance to GM dealers when using tire force variation measurement equipment, such as the Hunter GSP9700. This type of equipment can be a valuable tool in diagnosing vehicle ride concerns. The most common ride concern involving tire radial force variation is highway speed shake on smooth roads. Tire related smooth road highway speed shake can be caused by three conditions: imbalance, out of round and tire force variation. These three conditions are not necessarily related. All three conditions must be addressed. Imbalance is normally addressed first, because it is the simpler of the three to correct. Off-vehicle, two plane dynamic wheel balancers are readily available and can accurately correct any imbalance. Balancer calibration and maintenance, proper attachment of the wheel to the balancer, and proper balance weights, are all factors required for a quality balance. However, a perfectly balanced tire/wheel assembly can still be "oval shaped" and cause a vibration. Before balancing, perform the following procedures. Tire and Wheel Diagnosis 1. Set the tire pressure to the placard values. 2. With the vehicle raised, ensure the wheels are centered on the hub by loosening all wheel nuts and hand-tightening all nuts first by hand while shaking the wheel, then torque to specifications using a torque wrench, NOT a torque stick. 3. Visually inspect the tires and the wheels. Inspect for evidence of the following conditions and correct as necessary: - Missing balance weights - Bent rim flange - Irregular tire wear - Incomplete bead seating - Tire irregularities (including pressure settings) - Mud/ice build-up in wheel - Stones in the tire tread - Remove any aftermarket wheels and/or tires and restore vehicle to original condition prior to diagnosing a smooth road shake condition. 4. Road test the vehicle using the Electronic Vibration Analyzer (EVA) essential tool. Drive for a sufficient distance on a known, smooth road surface to duplicate the condition. Determine if the vehicle is sensitive to brake apply. If the brakes are applied lightly and the pulsation felt in the steering wheel increases, refer to the Brakes section of the service manual that deals with brake-induced pulsation. If you can start to hear the vibration as a low boom noise (in addition to feeling it), but cannot see it, the vehicle likely has a first order (one pulse per propshaft revolution) driveline vibration. Driveline first order vibrations are high enough in frequency that most humans can start to hear them at highway speeds, but are too high to be able to be easily seen. These issues can be caused by driveline imbalance or misalignment. If the vehicle exhibits this low boom and the booming pulses in-and-out on a regular basis (like a throbbing), chances are good that the vehicle could have driveline vibration. This type Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 1896 of vibration is normally felt more in the "seat of the pants" than the steering wheel. 5. Next, record the Hertz (Hz) reading as displayed by the EVA onto the tire data worksheet found at the end of this bulletin. This should be done after a tire break-in period of at least 16 km (10 mi) at 72 km/h (45 mph) or greater, in order to eliminate any possible tire flat-spotting. This reading confirms what the vehicle vibration frequency is prior to vehicle service and documents the amount of improvement occurring as the result of the various steps taken to repair. Completing the Steering Wheel Shake Worksheet below is required. A copy of the completed worksheet must be saved with the R.O. and a copy included with any parts returned to the Warranty Parts Center for analysis. A reading of 35 to 50 Hz typically indicates a first order propshaft vibration. If this is the situation, refer to Corporate Bulletin Number 08-07-30-044D. Generally, a reading between 10 and 20 Hz indicates a tire/wheel vibration and if this is the reading obtained, continue using this bulletin. If the tire 1st order vibration goes away and stays away during this evaluation, the cause is likely tire flat-spotting. Tire flat-spotting vibration may come and go at any speed over 72 km/h (45 mph) during the first 10 minutes of operation, if vibration continues after 10 minutes of driving at speeds greater than 72 km/h (45 mph), tire flat-spotting can be ruled out as the cause for vibration. 6. If flat-spotting is the cause, provide the explanation that this has occurred due to the vehicle being parked for long periods of time and that the nature of the tire is to take a set. Refer to Corporate Bulletin Number 03-03-10-007E: Information on Tire/Wheel Characteristics (Vibration, Balance, Shake, Flat Spotting) of GM Original Equipment Tires. 7. If the road test indicates a shake/vibration exists, check the imbalance of each tire/wheel assembly on a known, calibrated, off-car dynamic balancer.Make sure the mounting surface of the wheel and the surface of the balancer are absolutely clean and free of debris. Be sure to chose the proper cone/collet for the wheel, and always use the pilot bore for centering. Never center the wheel using the hub-cap bore since it is not a precision machined surface. If any assembly calls for more than 1/4 ounce on either rim flange, remove all balance weights and rebalance to as close to zero as possible. If you can see the vibration (along with feeling it) in the steering wheel (driving straight without your hands on the wheel), it is very likely to be a tire/wheel first order (one pulse per revolution) disturbance. First order disturbances can be caused by imbalance as well as non-uniformities in tires, wheels or hubs. This first order frequency is too low for a human to hear, but if the amplitude is high enough, it can be seen. If a vibration or shake still exists after balancing, any out of round conditions, of the wheel, and force variation conditions of the tire, must be addressed. Equipment such as the Hunter GSP9700 can address both (it is also a wheel balancer). Tire radial force vibration (RFV) can be defined as the amount of stiffness variation the tire will produce in one revolution under a constant load. Radial force variation is what the vehicle feels because the load (weight) of the vehicle is always on the tires. Although free runout of tires (not under load) is not always a good indicator of a smooth ride, it is critical that total tire/wheel assembly runout be within specification. Equipment such as the Hunter GSP9700 loads the tire, similar to on the vehicle, and measures radial force variation of the tire/wheel assembly. Note that the wheel is affecting the tire's RFV measurement at this point. To isolate the wheel, its runout must be measured. This can be easily done on the Hunter, without the need to set up dial indicators. If the wheel meets the runout specification, the tire's RFV can then be addressed. After measuring the tire/wheel assembly under load, and the wheel alone, the machine then calculates (predicts) the radial force variation of the tire. However, because this is a prediction that can include mounting inaccuracies, and the load wheel is much smaller in diameter than used in tire production, this type of service equipment should NOT be used to audit new tires. Rather, it should be used as a service diagnostic tool to minimize radial force variation of the tire/wheel assembly. Equipment such as the Hunter GSP9700 does an excellent job of measuring wheel runout, and of finding the low point of the wheel (for runout) and the high point of the tire (for radial force variation). This allows the tire to be matched mounted to the wheel for lowest tire/wheel assembly force variation. The machine will simplify this process into easy steps. The following assembly radial force variation numbers should be used as a guide: When measuring RFV and match mounting tires perform the following steps. Measuring Wheel Runout and Assembly Radial Force Variation Important The completed worksheet at the end of this bulletin must be attached to the hard copy of the repair order. - Measure radial force variation and radial runout. - If a road force/balancing machine is used, record the radial force variation (RFV) on the worksheet at the end of this bulletin. It may be of benefit to have the lowest RFV assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires onto the subject vehicle. - If a runout/balancing machine is used, record the radial runout of the tire/wheel assemblies on the worksheet at the end of this bulletin. If one or more of the tire/wheel assemblies are more than.040 in (1.02 mm), match mount the tire to the wheel to get below.040 in (1.02 mm). For sensitive customers, readings of 0.030 inch (0.76 mm) or less are preferable, it may also be of benefit to have the lowest runout assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 1897 onto the subject vehicle. - After match mounting, the tire/wheel assembly must be rebalanced. If match mounting tires to in-spec wheels produces assembly values higher than these, tire replacement may be necessary. Replacing tires at lower values will probably mean good tires are being condemned. Because tires can sometimes become temporarily flat-spotted, which will affect force variation, it is important that the vehicle be driven at least 16 km (10 mi) prior to measuring. Tire pressure must also be adjusted to the usage pressure on the vehicle's tire placard prior to measuring. Most GM vehicles will tolerate radial force variation up to these levels. However, some vehicles are more sensitive, and may require lower levels. Also, there are other tire parameters that equipment such as the Hunter GSP9700 cannot measure that may be a factor. In such cases, TAC should be contacted for further instructions. Important - When mounting a GM wheel to a wheel balancer/force variation machine, always use the wheel's center pilot hole. This is the primary centering mechanism on all GM wheels; the bolt holes are secondary. Usually a back cone method to the machine should be used. For added accuracy and repeatability, a flange plate should be used to clamp the wheel onto the cone and machine. This system is offered by all balancer manufacturers in GM's dealer program. - Any type of service equipment that removes tread rubber by grinding, buffing or truing is NOT recommended, and may void the tire warranty. However, tires may have been ground by the tire company as part of their tire manufacturing process. This is a legitimate procedure. Steering Wheel Shake Worksheet When diagnosing vibration concerns, use the following worksheet in conjunction with the appropriate Vibration Analysis-Road testing procedure in the Vibration Correction sub-section in SI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 1898 Refer to the appropriate section of SI for specifications and repair procedures that are related to the vibration concern. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels Wheels: All Technical Service Bulletins Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels TECHNICAL Bulletin No.: 05-03-10-003F Date: April 27, 2010 Subject: Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X with Cast Aluminum Wheels Supercede: This bulletin is being revised to update the model years and the bulletin reference information. Please discard Corporate Bulletin Number 05-03-10-003E (Section 03 - Suspension). Condition Some customers may comment on a low tire pressure condition. Diagnosis of the low tire pressure condition indicates an air leak through the cast aluminum wheel. Cause Porosity in the cast aluminum wheel may be the cause. Notice This bulletin specifically addresses issues related to the wheel casting that may result in an air leak. For issues related to corrosion of the wheel in service, please refer to Corporate Bulletin Number 08-03-10-006C - Tire Slowly Goes Flat, Tire Air Loss, Low Tire Pressure Warning Light Illuminated, Aluminum Wheel Bead Seat Corrosion (Clean and Resurface Wheel Bead Seat). Correction 1. Remove the tire and wheel assembly from the vehicle. Refer to the appropriate service procedure in SI. 2. Locate the leaking area by inflating the tire to 276 kPa (40 psi) and dipping the tire/wheel assembly in a water bath, or use a spray bottle with soap and water to locate the specific leak location. Important - If the porosity leak is located in the bead area of the aluminum rim (where the tire meets the rim), the wheel should be replaced. - If two or more leaks are located on one wheel, the wheel should be replaced. 3. If air bubbles are observed, mark the location. - If the leak location is on the tire/rubber area, refer to Corporate Bulletin Number 04-03-10-001F Tire Puncture Repair Procedures for All Cars and Light Duty Trucks. - If the leak is located on the aluminum wheel area, continue with the next step. 4. Inscribe a mark on the tire at the valve stem in order to indicate the orientation of the tire to the wheel. 5. Dismount the tire from the wheel. Refer to Tire Mounting and Dismounting. 6. Remove the tire pressure sensor. Refer to Tire Pressure Sensor removal procedure in SI. 7. Scuff the INSIDE rim surface at the leak area with #80 grit paper and clean the area with general purpose cleaner, such as 3M(R) General Purpose Adhesive Cleaner, P/N 08984, or equivalent. 8. Apply a 3 mm (0.12 in) thick layer of Silicone - Adhesive/Sealant, P/N 12378478 (in Canada, use 88900041), or equivalent, to the leak area. 9. Allow for the adhesive/sealant to dry. Notice Caution must be used when mounting the tire so as not to damage the sealer. Damaging the repair area may result in an air leak. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels > Page 1903 10. Align the inscribed mark on the tire with the valve stem on the wheel. 11. Reinstall the Tire Pressure Sensor. Refer to Tire Pressure Sensor installation procedure in SI. 12. Mount the tire on the wheel. Refer to Tire Mounting and Dismounting. 13. Pressurize the tire to 276 kPa (40 psi) and inspect for leaks. 14. Adjust tire pressure to meet the placard specification. 15. Balance the tire/wheel assembly. Refer to Tire and Wheel Assembly Balancing - Off-Vehicle. 16. Install the tire and wheel assembly onto the vehicle. Refer to the appropriate service procedure in SI. Parts Information Warranty Information (excluding Saab U.S. Models) Important The Silicone - Adhesive/Sealant comes in a case quantity of six. ONLY charge warranty one tube of adhesive/sealant per wheel repair. For vehicles repaired under warranty, use: One leak repair per wheel. Warranty Information (Saab U.S. Models) For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 04-03-10-012B > Feb > 08 > Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Bulletin No.: 04-03-10-012B Date: February 01, 2008 INFORMATION Subject: Pitting and Brake Dust on Chrome wheels Models: 2008 and Prior GM Passenger Cars and Trucks (including Saturn) 2008 and Prior HUMMER H2, H3 2005-2008 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 04-03-10-012A (Section 03 - Suspension). Analysis of Returned Wheels Chrome wheels returned under the New Vehicle Limited Warranty for pitting concerns have recently been evaluated. This condition is usually most severe in the vent (or window) area of the front wheels. This "pitting" may actually be brake dust that has been allowed to accumulate on the wheel. The longer this accumulation builds up, the more difficult it is to remove. Cleaning the Wheels In all cases, the returned wheels could be cleaned to their original condition using GM Vehicle Care Cleaner Wax, P/N 12377966 (in Canada, P/N 10952905). When using this product, you should confine your treatment to the areas of the wheel that show evidence of the brake dust build-up. This product is only for use on chromed steel or chromed aluminum wheels. Parts Information Warranty Information Wheel replacement for this condition is NOT applicable under the terms of the New Vehicle Limited Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 99-03-10-102 > Jun > 99 > Warranty - OE Chrome Plated Aluminum Wheel ID Wheels: All Technical Service Bulletins Warranty - OE Chrome Plated Aluminum Wheel ID File In Section: 03 - Suspension Bulletin No.: 99-03-10-102 Date: June, 1999 INFORMATION Subject: Original Equipment Chrome Plated Aluminum Wheel Identification Models: 1999 and Prior Passenger Cars and Light Duty Trucks Chrome plated aluminum wheels have been returned to the Warranty Parts Center that are not the original equipment (OE) components. Original equipment chrome plated aluminum wheels can be identified by either a balance weight clip retention groove (1) or a step (2) that is machined around both of the wheel's rim flanges. The rim flanges (3) of painted original equipment aluminum wheels do not have a groove or a step. Chrome plated aluminum wheels that do not have the wheel rim flange groove or step are aftermarket chrome plated components and are NOT warrantable. Any aftermarket chrome wheels received by the Warranty Parts Center will be charged back to the dealership. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 72-05-05 > Aug > 97 > Warranty - Guidelines for Using E0420 Wheel Replace Wheels: All Technical Service Bulletins Warranty - Guidelines for Using E0420 Wheel Replace File In Section: Warranty Administration Bulletin No.: 72-05-05 Date: August, 1997 WARRANTY ADMINISTRATION Subject: Guidelines for Using EO42O Wheel Replace Models: 1989-98 Passenger Cars and Light Duty Trucks The purpose of this bulletin is to provide service personnel with guidelines for using the above subject labor operation. Effective with repair orders dated on or after September 1, 1997, dealers are to be guided by the following: ^ Aluminum Wheels (including chrome plated) with Porosity - Wheels that exhibit porosity should be repaired as described in the vehicle service manual. Wheels should not be replaced without wholesale approval. ^ Aluminum Wheels (except chrome plated) with a "Finish Defect" - Wheels that exhibit a defect in the finish, (i.e., discoloration or surface degradation) should be refinished as described in the Corporate Service Bulletin Number 53-17-03A released in May, 1996. ^ Chrome Wheels - Wheels that are chromed and found to have a finish defect can only be replaced. ^ Aluminum and chrome wheels replaced under warranty will be subject to random part review and inspection. Those wheels inspected and found not to be defective and/or should have been repaired, will be subject to charge back. Wheels damaged by normal wear, road hazards, car wash brushes, or other physical or chemical damage are not eligible for warranty coverage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing Technical Service Bulletin # 531703A Date: 960501 Aluminum Wheels - Refinishing File In Section: 10 - Body Bulletin No.: 53-17-03A Date: May, 1996 INFORMATION Subject: Aluminum Wheel Refinishing Models: 1991-96 Passenger Cars and Trucks This bulletin is being revised to delete the 1990 model year and add the 1996 model year. Please discard Corporate Bulletin Number 53-17-03 (Section 10 - Body). This bulletin supersedes and cancels all previous service bulletins concerning the refinishing of aluminum wheels. The purpose of this service bulletin is to assist dealerships in repairing the discoloration or surface degradation that has occurred on styled aluminum wheels. This bulletin provides NEW PROCEDURES AND SPECIFIC MATERIALS for the refinishing of painted aluminum wheels or aluminum wheels with discoloration or surface degradation. Important: THE RE-MACHINING OF ALUMINUM WHEELS IS NOT RECOMMENDED. THE RE-CLEAR COATING OF ALUMINUM WHEELS IS NO LONGER RECOMMENDED DUE TO CONCERNS OF REPAIR DURABILITY The new procedure requires the wheel surface be plastic media blasted to remove old paint or clear coat. CHEMICAL STRIPPERS ARE NOT RECOMMENDED. Material Required System 1: DuPont Products 3939-S Cleaning Solvent 615/616 Etching Primer URO 5000 Primer Surfacer IMRON 6000 Basecoat 3440-S IMRON Clear System 2: PPG Products DX533 Aluminum Cleaner DX503 Aluminum Conditioner DP Epoxy Primer Deltron Basecoat (DBC) Concept 2001 Clear Acrylic Urethane System 3: Spies Hecker Permahyd Silicone Remover 7090 Permahyd 1:1 Primer 4070 Permahyd 2:1 Surfacer 5080 Permahyd Base Coat Series 280/285 Permahyd H.S. Clearcoat 8060 Color Selection If the wheels being painted were previously clearcoated aluminum, we would recommend using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option to the customer, you may also use body color. For color Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing > Page 1920 selection and verification, refer to your paint manufacturer's color book. On wheels that were previous clearcoated aluminum it is recommended that all four wheels and their center caps be refinished to maintain color uniformity. Important: THE PRODUCTS LISTED MUST BE USED AS A SYSTEM. DO NOT MIX OTHER MANUFACTURERS' PRODUCT LINES WITH THE REQUIRED MATERIALS. PRODUCTS LISTED IN THIS BULLETIN HAVE SHOWN THE REQUIRED REPAIR DURABILITY, AND CURRENTLY ARE THE ONLY PAINT SYSTEMS THAT MEET GM SPECIFICATION 4350M-A336. Procedures 1. Remove wheels from vehicle. Tires may remain mounted on wheels. 2. Remove balance weights and mark their location on tire. 3. Wipe excess grease, etc. from wheels with wax and grease remover. 4. Have wheels plastic media blasted to remove clearcoat. FOR FURTHER INFORMATION ON MEDIA BLASTING IN YOUR AREA, CALL US TECHNOLOGIES INC., CONTACT DAVE ROSENBURG AT 1-800-634-9185. Caution: IT IS MANDATORY THAT ADEQUATE RESPIRATORY PROTECTION BE WORN. EXAMPLES OF SUCH PROTECTION ARE: AIR LINE RESPIRATORS WITH FULL HOOD OR HALF MASK. IF NOT AVAILABLE, USE A VAPOR/PARTICULATE RESPIRATOR THAT RESPIRATOR MANUFACTURER RECOMMENDS AS EFFECTIVE FOR ISOCYANATE VAPOR AND MISTS (UNLESS LOCAL REGULATIONS PREVAIL). 5. Painting Process a. Refer to Attachments 1-3 for each System's individual formula and process. b. After following the specific System's individual formula and process, follow these steps: 6. Unmask wheels. 7. Clean all wheel mounting surface of any corrosion, overspray, or dirt. 8. Install new coated balance weights, at marked locations. 9. Replace wheels on vehicle. 10. USE A TORQUE STICK ON AN IMPACT WRENCH, OR A TORQUE WRENCH TO CONSISTENTLY AND UNIFORMLY FASTEN THE WHEEL TO THE SPECIFIED TORQUE FOR THE VEHICLE. THE STAR PATTERN MUST BE FOLLOWED. Important: TORQUE STICKS MUST BE USED ANY TIME AN IMPACT WRENCH IS USED TO TIGHTEN WHEEL NUTS. Warranty Information For vehicles repaired under warranty, use as shown. Attachment 1 - DuPont Products Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing > Page 1921 Painting Process System: Dupont Products Paint Color Information: Corsican Silver WA EQ9283 Dupont # C9143, Sparkle Silver WA9967 Dupont # C9339 1. Wipe wheel with cleaning solvent: 3939-S, 3949-S or 3900-S. 2. Mask off tires. Important: 3. Mask off all wheel mounting surfaces and wheel mount surfaces. 4. Apply two coats of 615/616-S etching primer to wheel allowing 10 minutes flash between coats. Allow to dry for 30 minutes before applying primer coat. 5. Apply URO 5000 primer 1220/193-S + accelerator 389-S using two coats at 65-70 PSI at the gun. Allow 12-15 minutes between coats. Force bake 30 minutes at 140°F (60°C). 6. Scuff sand using green Scotch-Brite pad. 7. Solvent wipe before top coating. 8. Apply IMRON 6000 base coat to wheel. 2-3 coats to hiding at 60-70 PSI allowing to flash between coats. Base coat needs to dry 20-30 minutes before clearcoat is applied. 9. Apply 3440-S clearcoat to wheel using two coats at 60-70 PSI. Flash 10-15 minutes between coats. 389-S can be used in basecoat and clearcoat to give faster set up times. 10. Allow overnight dry before reassemble. Can be baked for 30 minutes at 140°F (60°C). Attachment 2 - PPG Products Painting Process: PPG System Paint Color Information: Corsican Silver WAEQ9283; PPG # DBC-3531, Sparkle Silver WA9967; PPG # 35367 1. Wash entire wheel with aluminum cleaner DX533, mix 1:3 with water. Allow to react 2-3 minutes and rinse thoroughly. 2. Wash entire wheel with aluminum conditioner DX5O3 straight from the container. Allow to react 2-3 minutes until pale gold or tan color develops. Rinse thoroughly and dry. 3. Mask off tires. Important: 4. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 5. Apply 1-2 coats of DP Primer and allow to flash for 15-20 minutes. 6. Apply 2-3 coats of Deltron Basecoat (DBC) and allow to flash 20 minutes after the final coat. 7. Apply two (2) wet coats of Concept 2001 Acrylic urethane. 8. Flash 20 minutes and bake 140°F (60°C) for 30 minutes. For more information contact your PPG Jobber. Attachment 3 - Spies Hecker Painting Process: Spies Hecker System Paint Color Information: Corsican Silver AWEQ9283; SH-72913, Sparkle Silver WA9967; SH-71912 1. Clean with Permahyd Silicone Remover 7090. 2. Mask off tires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing > Page 1922 Important: 3. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 4. Apply 1-1/2 coats of Permahyd 1:1 Primer 4070. Mix 1:1 with Permahyd Hardener 3070 as per TDS. 5. Allow to flash for 30 minutes. 6. Apply two (2) coats of Permahyd 2:1 Surfacer 5080. Mix 2:1 with Permahyd Hardener 3071 as per TDS. 7. Bake for 60 minutes at 140°F (60°C) or allow to flash for 3 hours at 68°F (20°C). 8. Apply Permahyd Base Coat Series 280/285 as per TDS. 9. Allow to flash 10 to 15 minutes. 10. Apply 1 to 2 coats of Permacron High Solid Clear Coat 8060 as per TDS. 11. Allow to flash 10 minutes. Then bake at 140°F (60°C) for 40 minutes. For more information, contact your SPIES HECKER Jobber. We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Staining/Pitting/Corrosion INFORMATION Bulletin No.: 00-03-10-002F Date: April 21, 2011 Subject: Chemical Staining, Pitting, Corrosion and/or Spotted Appearance of Chromed Aluminum Wheels Models: 2012 and Prior GM Cars and Trucks Supercede: This bulletin is being revised to update model years, suggest additional restorative products and add additional corrosion information. Please discard Corporate Bulletin Number 00-03-10-002E (Section 03 - Suspension). Important You may give a copy of this bulletin to the customer. What is Chemical Staining of Chrome Wheels? Figure 1 Chemical staining in most cases results from acid based cleaners (refer to Figure 1 for an example). These stains are frequently milky, black, or greenish in appearance. They result from using cleaning solutions that contain acids on chrome wheels. Soap and water is usually sufficient to clean wheels. If the customer insists on using a wheel cleaner they should only use one that specifically states that it is safe for chromed wheels and does not contain anything in the following list. (Dealers should also survey any products they use during prep or normal cleaning of stock units for these chemicals.) - Ammonium Bifluoride (fluoride source for dissolution of chrome) - Hydrofluoric Acid (directly dissolves chrome) - Hydrochloric Acid (directly dissolves chrome) - Sodium Dodecylbenzenesulfonic Acid - Sulfamic Acid - Phosphoric Acid - Hydroxyacetic Acid Notice Many wheel cleaner instructions advise to take care to avoid contact with painted surfaces. Most customers think of painted surfaces as the fenders, quarter panels and other exterior sheet metal. Many vehicles have painted brake calipers. Acidic wheel cleaners may craze, crack, or discolor the paint on the brake calipers. Damage from wheel cleaners is not covered under the vehicle new car warranty. Soap and water applied with a soft brush is usually all that is required to clean the calipers. Whenever any wheel cleaner is used, it must be THOROUGHLY rinsed off of the wheel with clean, clear water. Special care must be taken to rinse under the hub cap, balance weights, wheel nuts, lug nut caps, between the wheel cladding and off the back side of the wheel. Wheels returned to the Warranty Parts Center (WPC) that exhibit damage from wheel cleaners most often have the damage around and under the wheel weight where the cleaner was incompletely flushed away. Notice Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 1928 Do not use cleaning solutions that contain hydrofluoric, oxalic and most other acids on chrome wheels (or any wheels). If the customer is unsure of the chemical make-up of a particular wheel cleaner, it should be avoided. For wheels showing signs of milky staining from acidic cleaners, refer to Customer Assistance and Instructions below. Warranty of Stained Chrome Wheels Stained wheels are not warrantable. Most acid based cleaners will permanently stain chrome wheels. Follow-up with dealers has confirmed that such cleaners were used on wheels that were returned to the Warranty Parts Center (WPC). Any stained wheels received by the WPC will be charged back to the dealership. To assist the customer, refer to Customer Assistance and Instructions below. Pitting or Spotted Appearance of Chrome Wheels Figure 2 A second type or staining or finish disturbance may result from road chemicals, such as calcium chloride used for dust control of unpaved roads. The staining will look like small pitting (refer to Figure 2). This staining will usually be on the leading edges of each wheel spoke, but may be uniformly distributed. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Important Road chemicals, such as calcium chloride used for dust control of unpaved roads, can also stain chrome wheels. The staining will look like small pitting. This staining will usually be on the leading edges of each wheel spoke. This is explained by the vehicle traveling in the forward direction while being splashed by the road chemical. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Warranty of Pitted or Spotted Chrome Wheels Wheels returned with pitting or spotting as a result of road chemicals may be replaced one time. Damage resulting from contact with these applied road chemicals is corrosive to the wheels finish and may cause damage if the wheels are not kept clean. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean if they are operating the vehicle in an area that applies calcium chloride or other dust controlling chemicals! "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). "Stardust" Corrosion of Chrome Wheels Figure 3 A third type of finish disturbance results from prolonged exposure to brake dust and resultant penetration of brake dust through the chrome. As brakes are applied hot particles of brake material are thrown off and tend to be forced through the leading edge of the wheel spoke windows by airflow. These Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 1929 hot particles embed themselves in the chrome layer and create a small pit. If the material is allowed to sit on the wheel while it is exposed to moisture or salt, it will corrode the wheel beneath the chrome leaving a pit or small blister in the chrome. Heavy brake dust build-up should be removed from wheels by using GM Chrome Cleaner and Polish, P/N 1050173 (in Canada use 10953013). For moderate cleaning, light brake dust build-up or water spots use GM Swirl Remover Polish, P/N 12377965 (in Canada, use Meguiars Plast-X(TM) Clear Plastic Cleaner and Polish #G12310C**). After cleaning, the wheel should be waxed using GM Cleaner Wax, P/N 12377966 (in Canada, use Meguiars Cleaner Wax #M0616C**), which will help protect the wheel from brake dust and reduce adhesion of any brake dust that gets on the wheel surface. For general maintenance cleaning, PEEK Metal Polish† may be used. It will clean and shine the chrome and leave behind a wax coating that may help protect the finish. Warranty of Stardust Corroded Chrome Wheels Wheels returned with pitting or spotting as a result of neglect and brake dust build-up may be replaced one time. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean and free of prolonged exposure to brake dust build-up. "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). Customer Assistance and Instructions GM has looked for ways customers may improve the appearance of wheels damaged by acidic cleaners. The following product and procedure has been found to dramatically improve the appearance of stained wheels. For wheels that have milky stains caused by acidic cleaners try the following: Notice THE 3M CHROME AND METAL POLISH REQUIRED FOR THIS PROCEDURE IS AN EXTREMELY AGGRESSIVE POLISH/CLEANER. THE WHEELS MUST BE CLEANED BEFORE APPLICATION TO AVOID SCRATCHING THE WHEEL SURFACE. THIS PRODUCT WILL REDUCE THE THICKNESS OF THE CHROME PLATING ON THE WHEEL AND IF USED INCORRECTLY OR EXCESSIVELY MAY REMOVE THE CHROME PLATING ALL TOGETHER, EXPOSING A LESS BRIGHT AND BRASSY COLORED SUB-LAYER. FOLLOW INSTRUCTIONS EXACTLY. 1. Wash the wheels with vigorously with soap and water. This step will clean and may reduce wheel staining. Flood all areas of the wheel with water to rinse. 2. Dry the wheels completely. Notice Begin with a small section of the wheel and with light pressure buff off polish and examine results. ONLY apply and rub with sufficient force and time to remove enough staining that you are satisfied with the results. Some wheels may be stained to the extent that you may only achieve a 50% improvement while others may be able to be restored to the original lustre. IN ALL CASES, only apply until the results are satisfactory. 3. Apply 3M Chrome and Metal Polish #39527* with a clean terry cloth towel. As you apply the polish, the staining will be diminished. 4. When dry, buff off the polish with a clean portion of the towel. 5. Repeat application of the 3M Chrome and Metal Polish until satisfied with the results. If continued applications fail to improve the appearance further discontinue use. This procedure will improve the appearance of the wheels and may, with repeated applications, restore the finish dramatically. For wheels that exhibit spotting from road chemicals the above procedure may marginally improve the condition but will not restore the finish or remove the pitting. In this type of staining the wheel finish has actually been removed in spots and no manner of cleaning will restore the finish. †*We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Parts Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 1930 *This product is currently available from 3M. To obtain information for your local retail location please call 3M at 1-888-364-3577. **This product is currently available from Meguiars (Canada). To obtain information for your local retail location please call Meguiars at 1-800-347-5700 or at www.meguiarscanada.com. ^ This product is currently available from Tri-Peek International. To obtain information for your local retail location please call Tri-Peek at 1-877-615-4272 or at www.tripeek.com. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires - Refinishing Aluminum Wheels Wheels: All Technical Service Bulletins Wheels/Tires - Refinishing Aluminum Wheels INFORMATION Bulletin No.: 99-08-51-007E Date: March 17, 2011 Subject: Refinishing Aluminum Wheels Models: 2012 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 99-08-51-007D (Section 08 - Body and Accessories). This bulletin updates General Motor's position on refinishing aluminum wheels. GM does not endorse any repairs that involve welding, bending, straightening or re-machining. Only cosmetic refinishing of the wheel's coatings, using recommended procedures, is allowed. Evaluating Damage In evaluating damage, it is the GM Dealer's responsibility to inspect the wheel for corrosion, scrapes, gouges, etc. The Dealer must insure that such damage is not deeper than what can be sanded or polished off. The wheel must be inspected for cracks. If cracks are found, discard the wheel. Any wheels with bent rim flanges must not be repaired or refinished. Wheels that have been refinished by an outside company must be returned to the same vehicle. The Dealer must record the wheel ID stamp or the cast date on the wheel in order to assure this requirement. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. Aluminum Wheel Refinishing Recommendations - Chrome-plated aluminum wheels Re-plating these wheels is not recommended. - Polished aluminum wheels These wheels have a polyester or acrylic clearcoat on them. If the clearcoat is damaged, refinishing is possible. However, the required refinishing process cannot be performed in the dealer environment. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. - Painted aluminum wheels These wheels are painted using a primer, color coat, and clearcoat procedure. If the paint is damaged, refinishing is possible. As with polished wheels, all original coatings must be removed first. Media blasting is recommended. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for the re-painting of this type of wheel. - Bright, machined aluminum wheels These wheels have a polyester or acrylic clearcoat on them. In some cases, the recessed "pocket" areas of the wheel may be painted. Surface refinishing is possible. The wheel must be totally stripped by media blasting or other suitable means. The wheel should be resurfaced by using a sanding process rather than a machining process. This allows the least amount of material to be removed. Important Do not use any re-machining process that removes aluminum. This could affect the dimensions and function of the wheel. Painting is an option to re-clearcoating polished and bright machined aluminum wheels. Paint will better mask any surface imperfections and is somewhat more durable than clearcoat alone. GM recommends using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option, the body color may also be used. When using any of the painting options, it is recommended that all four wheels be refinished in order to maintain color uniformity. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for specific procedures and product recommendations. Refinisher's Responsibility - Outside Company Important Some outside companies are offering wheel refinishing services. Such refinished wheels will be permanently marked by the refinisher and are warranted by the refinisher. Any process that re-machines or otherwise re-manufactures the wheel should not be used. A refinisher's responsibility includes inspecting for cracks using the Zyglo system or the equivalent. Any cracked wheels must not be refinished. No welding, hammering or reforming of any kind is allowed. The wheel ID must be recorded and follow the wheel throughout the process in order to assure that the same wheel is returned. A plastic media blast may be used for clean up of the wheel. Hand and/or lathe sanding of the machined surface and the wheel window is allowed. Material removal, though, must be kept to a minimum. Re-machining of the wheel is not allowed. Paint and/or clear coat must not be present on the following surfaces: the nut chamfers, the wheel mounting surfaces and the wheel pilot hole. The refinisher must permanently ID stamp the wheel and warrant the painted/clearcoated surfaces for a minimum of one year or the remainder of the new vehicle warranty, whichever is Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires - Refinishing Aluminum Wheels > Page 1935 longer. Important Whenever a wheel is refinished, the mounting surface and the wheel nut contact surfaces must not be painted or clearcoated. Coating these surfaces could affect the wheel nut torque. When re-mounting a tire on an aluminum wheel, coated balance weights must be used in order to reduce the chance of future cosmetic damage. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions Wheels: All Technical Service Bulletins Wheels - Changing Procedures/Precautions INFORMATION Bulletin No.: 06-03-10-010A Date: June 09, 2010 Subject: Information on Proper Wheel Changing Procedures and Cautions Models: 2011 and Prior GM Passenger Cars and Trucks 2010 and Prior HUMMER Models 2005-2009 Saab 9-7X 2005-2009 Saturn Vehicles Attention: Complete wheel changing instructions for each vehicle line can be found under Tire and Wheel Removal and Installation in Service Information (SI). This bulletin is intended to quickly review and reinforce simple but vital procedures to reduce the possibility of achieving low torque during wheel installation. Always refer to SI for wheel lug nut torque specifications and complete jacking instructions for safe wheel changing. Supercede: This bulletin is being revised to include the 2011 model year and update the available special tool list. Please discard Corporate Bulletin Number 06-03-10-010 (Section 03 Suspension). Frequency of Wheel Changes - Marketplace Driven Just a few years ago, the increasing longevity of tires along with greater resistance to punctures had greatly reduced the number of times wheels were removed to basically required tire rotation intervals. Today with the booming business in accessory wheels/special application tires (such as winter tires), consumers are having tire/wheel assemblies removed - replaced - or installed more than ever. With this increased activity, it opens up more of a chance for error on the part of the technician. This bulletin will review a few of the common concerns and mistakes to make yourself aware of. Proper Servicing Starts With the Right Tools The following tools have been made available to assist in proper wheel and tire removal and installation. - J 41013 Rotor Resurfacing Kit (or equivalent) - J 42450-A Wheel Hub Resurfacing Kit (or equivalent) Corroded Surfaces One area of concern is corrosion on the mating surfaces of the wheel to the hub on the vehicle. Excessive corrosion, dirt, rust or debris built up on these surfaces can mimic a properly tightened wheel in the service stall. Once the vehicle is driven, the debris may loosen, grind up or be washed away from water splash. This action may result in clearance at the mating surface of the wheel and an under-torqued condition. Caution Before installing a wheel, remove any buildup on the wheel mounting surface and brake drum or brake disc mounting surface. Installing wheels with poor metal-to-metal contact at the mounting surfaces can cause wheel nuts to loosen. This may cause a wheel to come off when the vehicle is moving, possibly resulting in a loss of control or personal injury. Whenever you remove the tire/wheel assemblies, you must inspect the mating surfaces. If corrosion is found, you should remove the debris with a die grinder equipped with a fine sanding pad, wire brush or cleaning disc. Just remove enough material to assure a clean, smooth mating surface. The J 41013 (or equivalent) can be used to clean the following surfaces: - The hub mounting surface - The brake rotor mounting surface - The wheel mounting surface Use the J 42450-A (or equivalent) to clean around the base of the studs and the hub. Lubricants, Grease and Fluids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 1940 Some customers may use penetrating oils, grease or other lubricants on wheel studs to aid in removal or installation. Always use a suitable cleaner/solvent to remove these lubricants prior to installing the wheel and tire assemblies. Lubricants left on the wheel studs may cause improper readings of wheel nut torque. Always install wheels to clean, dry wheel studs ONLY. Notice Lubricants left on the wheel studs or vertical mounting surfaces between the wheel and the rotor or drum may cause the wheel to work itself loose after the vehicle is driven. Always install wheels to clean, dry wheel studs and surfaces ONLY. Beginning with 2011 model year vehicles, put a light coating of grease, GM P/N 1051344 (in Canada, P/N 9930370), on the inner surface of the wheel pilot hole to prevent wheel seizure to the axle or bearing hub. Wheel Stud and Lug Nut Damage Always inspect the wheel studs and lug nuts for signs of damage from crossthreading or abuse. You should never have to force wheel nuts down the stud. Lug nuts that are damaged may not retain properly, yet give the impression of fully tightening. Always inspect and replace any component suspected of damage. Tip Always start wheel nuts by hand! Be certain that all wheel nut threads have been engaged BEFORE tightening the nut. Important If the vehicle has directional tread tires, verify the directional arrow on the outboard side of the tire is pointing in the direction of forward rotation. Wheel Nut Tightening and Torque Improper wheel nut tightening can lead to brake pulsation and rotor damage. In order to avoid additional brake repairs, evenly tighten the wheel nuts to the proper torque specification as shown for each vehicle in SI. Always observe the proper wheel nut tightening sequence as shown below in order to avoid trapping the wheel on the wheel stud threads or clamping the wheel slightly off center resulting in vibration. The Most Important Service You Provide While the above information is well known, and wheel removal so common, technicians run the risk of becoming complacent on this very important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 1941 service operation. A simple distraction or time constraint that rushes the job may result in personal injury if the greatest of care is not exercised. Make it a habit to double check your work and to always side with caution when installing wheels. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 04-03-10-012B > Feb > 08 > Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Bulletin No.: 04-03-10-012B Date: February 01, 2008 INFORMATION Subject: Pitting and Brake Dust on Chrome wheels Models: 2008 and Prior GM Passenger Cars and Trucks (including Saturn) 2008 and Prior HUMMER H2, H3 2005-2008 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 04-03-10-012A (Section 03 - Suspension). Analysis of Returned Wheels Chrome wheels returned under the New Vehicle Limited Warranty for pitting concerns have recently been evaluated. This condition is usually most severe in the vent (or window) area of the front wheels. This "pitting" may actually be brake dust that has been allowed to accumulate on the wheel. The longer this accumulation builds up, the more difficult it is to remove. Cleaning the Wheels In all cases, the returned wheels could be cleaned to their original condition using GM Vehicle Care Cleaner Wax, P/N 12377966 (in Canada, P/N 10952905). When using this product, you should confine your treatment to the areas of the wheel that show evidence of the brake dust build-up. This product is only for use on chromed steel or chromed aluminum wheels. Parts Information Warranty Information Wheel replacement for this condition is NOT applicable under the terms of the New Vehicle Limited Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 99-03-10-102 > Jun > 99 > Warranty - OE Chrome Plated Aluminum Wheel ID Wheels: All Technical Service Bulletins Warranty - OE Chrome Plated Aluminum Wheel ID File In Section: 03 - Suspension Bulletin No.: 99-03-10-102 Date: June, 1999 INFORMATION Subject: Original Equipment Chrome Plated Aluminum Wheel Identification Models: 1999 and Prior Passenger Cars and Light Duty Trucks Chrome plated aluminum wheels have been returned to the Warranty Parts Center that are not the original equipment (OE) components. Original equipment chrome plated aluminum wheels can be identified by either a balance weight clip retention groove (1) or a step (2) that is machined around both of the wheel's rim flanges. The rim flanges (3) of painted original equipment aluminum wheels do not have a groove or a step. Chrome plated aluminum wheels that do not have the wheel rim flange groove or step are aftermarket chrome plated components and are NOT warrantable. Any aftermarket chrome wheels received by the Warranty Parts Center will be charged back to the dealership. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 72-05-05 > Aug > 97 > Warranty - Guidelines for Using E0420 Wheel Replace Wheels: All Technical Service Bulletins Warranty - Guidelines for Using E0420 Wheel Replace File In Section: Warranty Administration Bulletin No.: 72-05-05 Date: August, 1997 WARRANTY ADMINISTRATION Subject: Guidelines for Using EO42O Wheel Replace Models: 1989-98 Passenger Cars and Light Duty Trucks The purpose of this bulletin is to provide service personnel with guidelines for using the above subject labor operation. Effective with repair orders dated on or after September 1, 1997, dealers are to be guided by the following: ^ Aluminum Wheels (including chrome plated) with Porosity - Wheels that exhibit porosity should be repaired as described in the vehicle service manual. Wheels should not be replaced without wholesale approval. ^ Aluminum Wheels (except chrome plated) with a "Finish Defect" - Wheels that exhibit a defect in the finish, (i.e., discoloration or surface degradation) should be refinished as described in the Corporate Service Bulletin Number 53-17-03A released in May, 1996. ^ Chrome Wheels - Wheels that are chromed and found to have a finish defect can only be replaced. ^ Aluminum and chrome wheels replaced under warranty will be subject to random part review and inspection. Those wheels inspected and found not to be defective and/or should have been repaired, will be subject to charge back. Wheels damaged by normal wear, road hazards, car wash brushes, or other physical or chemical damage are not eligible for warranty coverage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing Technical Service Bulletin # 531703A Date: 960501 Aluminum Wheels - Refinishing File In Section: 10 - Body Bulletin No.: 53-17-03A Date: May, 1996 INFORMATION Subject: Aluminum Wheel Refinishing Models: 1991-96 Passenger Cars and Trucks This bulletin is being revised to delete the 1990 model year and add the 1996 model year. Please discard Corporate Bulletin Number 53-17-03 (Section 10 - Body). This bulletin supersedes and cancels all previous service bulletins concerning the refinishing of aluminum wheels. The purpose of this service bulletin is to assist dealerships in repairing the discoloration or surface degradation that has occurred on styled aluminum wheels. This bulletin provides NEW PROCEDURES AND SPECIFIC MATERIALS for the refinishing of painted aluminum wheels or aluminum wheels with discoloration or surface degradation. Important: THE RE-MACHINING OF ALUMINUM WHEELS IS NOT RECOMMENDED. THE RE-CLEAR COATING OF ALUMINUM WHEELS IS NO LONGER RECOMMENDED DUE TO CONCERNS OF REPAIR DURABILITY The new procedure requires the wheel surface be plastic media blasted to remove old paint or clear coat. CHEMICAL STRIPPERS ARE NOT RECOMMENDED. Material Required System 1: DuPont Products 3939-S Cleaning Solvent 615/616 Etching Primer URO 5000 Primer Surfacer IMRON 6000 Basecoat 3440-S IMRON Clear System 2: PPG Products DX533 Aluminum Cleaner DX503 Aluminum Conditioner DP Epoxy Primer Deltron Basecoat (DBC) Concept 2001 Clear Acrylic Urethane System 3: Spies Hecker Permahyd Silicone Remover 7090 Permahyd 1:1 Primer 4070 Permahyd 2:1 Surfacer 5080 Permahyd Base Coat Series 280/285 Permahyd H.S. Clearcoat 8060 Color Selection If the wheels being painted were previously clearcoated aluminum, we would recommend using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option to the customer, you may also use body color. For color Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing > Page 1958 selection and verification, refer to your paint manufacturer's color book. On wheels that were previous clearcoated aluminum it is recommended that all four wheels and their center caps be refinished to maintain color uniformity. Important: THE PRODUCTS LISTED MUST BE USED AS A SYSTEM. DO NOT MIX OTHER MANUFACTURERS' PRODUCT LINES WITH THE REQUIRED MATERIALS. PRODUCTS LISTED IN THIS BULLETIN HAVE SHOWN THE REQUIRED REPAIR DURABILITY, AND CURRENTLY ARE THE ONLY PAINT SYSTEMS THAT MEET GM SPECIFICATION 4350M-A336. Procedures 1. Remove wheels from vehicle. Tires may remain mounted on wheels. 2. Remove balance weights and mark their location on tire. 3. Wipe excess grease, etc. from wheels with wax and grease remover. 4. Have wheels plastic media blasted to remove clearcoat. FOR FURTHER INFORMATION ON MEDIA BLASTING IN YOUR AREA, CALL US TECHNOLOGIES INC., CONTACT DAVE ROSENBURG AT 1-800-634-9185. Caution: IT IS MANDATORY THAT ADEQUATE RESPIRATORY PROTECTION BE WORN. EXAMPLES OF SUCH PROTECTION ARE: AIR LINE RESPIRATORS WITH FULL HOOD OR HALF MASK. IF NOT AVAILABLE, USE A VAPOR/PARTICULATE RESPIRATOR THAT RESPIRATOR MANUFACTURER RECOMMENDS AS EFFECTIVE FOR ISOCYANATE VAPOR AND MISTS (UNLESS LOCAL REGULATIONS PREVAIL). 5. Painting Process a. Refer to Attachments 1-3 for each System's individual formula and process. b. After following the specific System's individual formula and process, follow these steps: 6. Unmask wheels. 7. Clean all wheel mounting surface of any corrosion, overspray, or dirt. 8. Install new coated balance weights, at marked locations. 9. Replace wheels on vehicle. 10. USE A TORQUE STICK ON AN IMPACT WRENCH, OR A TORQUE WRENCH TO CONSISTENTLY AND UNIFORMLY FASTEN THE WHEEL TO THE SPECIFIED TORQUE FOR THE VEHICLE. THE STAR PATTERN MUST BE FOLLOWED. Important: TORQUE STICKS MUST BE USED ANY TIME AN IMPACT WRENCH IS USED TO TIGHTEN WHEEL NUTS. Warranty Information For vehicles repaired under warranty, use as shown. Attachment 1 - DuPont Products Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing > Page 1959 Painting Process System: Dupont Products Paint Color Information: Corsican Silver WA EQ9283 Dupont # C9143, Sparkle Silver WA9967 Dupont # C9339 1. Wipe wheel with cleaning solvent: 3939-S, 3949-S or 3900-S. 2. Mask off tires. Important: 3. Mask off all wheel mounting surfaces and wheel mount surfaces. 4. Apply two coats of 615/616-S etching primer to wheel allowing 10 minutes flash between coats. Allow to dry for 30 minutes before applying primer coat. 5. Apply URO 5000 primer 1220/193-S + accelerator 389-S using two coats at 65-70 PSI at the gun. Allow 12-15 minutes between coats. Force bake 30 minutes at 140°F (60°C). 6. Scuff sand using green Scotch-Brite pad. 7. Solvent wipe before top coating. 8. Apply IMRON 6000 base coat to wheel. 2-3 coats to hiding at 60-70 PSI allowing to flash between coats. Base coat needs to dry 20-30 minutes before clearcoat is applied. 9. Apply 3440-S clearcoat to wheel using two coats at 60-70 PSI. Flash 10-15 minutes between coats. 389-S can be used in basecoat and clearcoat to give faster set up times. 10. Allow overnight dry before reassemble. Can be baked for 30 minutes at 140°F (60°C). Attachment 2 - PPG Products Painting Process: PPG System Paint Color Information: Corsican Silver WAEQ9283; PPG # DBC-3531, Sparkle Silver WA9967; PPG # 35367 1. Wash entire wheel with aluminum cleaner DX533, mix 1:3 with water. Allow to react 2-3 minutes and rinse thoroughly. 2. Wash entire wheel with aluminum conditioner DX5O3 straight from the container. Allow to react 2-3 minutes until pale gold or tan color develops. Rinse thoroughly and dry. 3. Mask off tires. Important: 4. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 5. Apply 1-2 coats of DP Primer and allow to flash for 15-20 minutes. 6. Apply 2-3 coats of Deltron Basecoat (DBC) and allow to flash 20 minutes after the final coat. 7. Apply two (2) wet coats of Concept 2001 Acrylic urethane. 8. Flash 20 minutes and bake 140°F (60°C) for 30 minutes. For more information contact your PPG Jobber. Attachment 3 - Spies Hecker Painting Process: Spies Hecker System Paint Color Information: Corsican Silver AWEQ9283; SH-72913, Sparkle Silver WA9967; SH-71912 1. Clean with Permahyd Silicone Remover 7090. 2. Mask off tires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels - Refinishing > Page 1960 Important: 3. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 4. Apply 1-1/2 coats of Permahyd 1:1 Primer 4070. Mix 1:1 with Permahyd Hardener 3070 as per TDS. 5. Allow to flash for 30 minutes. 6. Apply two (2) coats of Permahyd 2:1 Surfacer 5080. Mix 2:1 with Permahyd Hardener 3071 as per TDS. 7. Bake for 60 minutes at 140°F (60°C) or allow to flash for 3 hours at 68°F (20°C). 8. Apply Permahyd Base Coat Series 280/285 as per TDS. 9. Allow to flash 10 to 15 minutes. 10. Apply 1 to 2 coats of Permacron High Solid Clear Coat 8060 as per TDS. 11. Allow to flash 10 minutes. Then bake at 140°F (60°C) for 40 minutes. For more information, contact your SPIES HECKER Jobber. We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheel Bearing > Component Information > Adjustments Wheel Bearing: Adjustments FRONT WHEEL BEARINGS ADJUSTMENT Fig. 2 Front Wheel Bearing Adjustment 1. While rotating wheel forward, torque spindle nut to 12 ft. lbs., Fig. 2. 2. Back off nut until just loose then hand tighten nut and back it off again until either hole in spindle lines up with hole in nut. Do not back off nut more than 1/2 flat. 3. Install new cotter pin. With wheel bearing properly adjusted, there will be .001-.005 inch end play. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheel Bearing > Component Information > Adjustments > Page 1964 Wheel Bearing: Service and Repair FRONT WHEEL BEARINGS Fig. 3 Hub & Wheel Bearing Replacement 1. Raise car and remove front wheels. 2. On models equipped with anti-lock brake systems, remove right and left wheel speed sensors as follows: a. Under vehicle hood, disconnect speed sensor electrical harness. b. Raise and support vehicle, then remove speed sensor harness bracket attaching bolt. c. Remove speed sensor to steering knuckle attaching bolt, then remove speed sensor and bracket assembly and position aside. d. Reverse procedure to install. Install wheel speed sensors by hand. Do not hammer sensors into position, as damage may result. 3. On all models, remove bolts holding brake caliper to its mounting and insert a fabricated block (11/16 x 1 1/16 x 2 inches in length) between brake pads as caliper is being removed. Once removed, caliper can be wired or secured in some manner away from disc. 4. Remove spindle nut and hub and disc assembly. Grease retainer and inner wheel bearing can now be removed, Fig. 3. 5. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > Customer Interest for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels - Plastic Wheel Nut Covers Loose/Missing Wheel Fastener: Customer Interest Wheels - Plastic Wheel Nut Covers Loose/Missing Bulletin No.: 01-03-10-009A Date: July 27, 2004 TECHNICAL Subject: Plastic Wheel Nut Covers Missing and/or Loose (Replace Missing Covers and Add Sealant to All Covers) Models: 2005 and All Prior Passenger Cars (Except All Cadillac Models and Pontiac GTO) with Plastic Wheel Nut Covers Supercede: This bulletin is being revised to add additional models years. Please discard Corporate Bulletin Number 01-03-10-009. Condition Some customers may comment that the plastic wheel nut covers are missing and/or loose. Correction Important: ^ DO NOT USE a silicone-based adhesive. ^ Do not apply the *permatex(R) around the threads in a circular pattern. ^ Apply a single bead across the threads approximately 10 mm (0.4 in) in length, 5 mm (0.2 in) in height and 5 mm (0.2 in) in width. Replace any missing plastic wheel nut covers with the appropriate covers and apply Permatex(R) # 2 Form A Gasket Sealant(R) to the threads of all the plastic wheel nut covers. Tighten finger tight plus a 1/4 turn with a hand wrench. *We believe this source and their products to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any other such items which may be available from other sources. Permatex(R) # 2 Form A Gasket Sealant(R) part numbers (available at your local parts supplier) ^ P/N 80009 (2A/2AR) - 44 ml (1.5 oz) tube boxed ^ P/N 80015 (2AR) - 44 ml (1.5 oz) tube carded ^ P/N 80010 (2B/2BR) - 89 ml (3 oz) tube boxed ^ P/N 80016 (2BR) - 89 ml (3 oz) tube carded ^ P/N 80011 (2C) - 325 ml (11 oz) tube boxed Warranty Information For vehicles repaired under warranty, use the table. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > Customer Interest for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels - Plastic Wheel Nut Covers Loose/Missing > Page 1973 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels - Plastic Wheel Nut Covers Loose/Missing Wheel Fastener: All Technical Service Bulletins Wheels - Plastic Wheel Nut Covers Loose/Missing Bulletin No.: 01-03-10-009A Date: July 27, 2004 TECHNICAL Subject: Plastic Wheel Nut Covers Missing and/or Loose (Replace Missing Covers and Add Sealant to All Covers) Models: 2005 and All Prior Passenger Cars (Except All Cadillac Models and Pontiac GTO) with Plastic Wheel Nut Covers Supercede: This bulletin is being revised to add additional models years. Please discard Corporate Bulletin Number 01-03-10-009. Condition Some customers may comment that the plastic wheel nut covers are missing and/or loose. Correction Important: ^ DO NOT USE a silicone-based adhesive. ^ Do not apply the *permatex(R) around the threads in a circular pattern. ^ Apply a single bead across the threads approximately 10 mm (0.4 in) in length, 5 mm (0.2 in) in height and 5 mm (0.2 in) in width. Replace any missing plastic wheel nut covers with the appropriate covers and apply Permatex(R) # 2 Form A Gasket Sealant(R) to the threads of all the plastic wheel nut covers. Tighten finger tight plus a 1/4 turn with a hand wrench. *We believe this source and their products to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any other such items which may be available from other sources. Permatex(R) # 2 Form A Gasket Sealant(R) part numbers (available at your local parts supplier) ^ P/N 80009 (2A/2AR) - 44 ml (1.5 oz) tube boxed ^ P/N 80015 (2AR) - 44 ml (1.5 oz) tube carded ^ P/N 80010 (2B/2BR) - 89 ml (3 oz) tube boxed ^ P/N 80016 (2BR) - 89 ml (3 oz) tube carded ^ P/N 80011 (2C) - 325 ml (11 oz) tube boxed Warranty Information For vehicles repaired under warranty, use the table. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels - Plastic Wheel Nut Covers Loose/Missing > Page 1979 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > Page 1980 Wheel Fastener: Specifications Wheel Nuts .......................................................................................................................................... ................................................ 140 Nm (100 ft lb) CAUTION: If penetrating oil gets on the vertical surfaces between the wheel and the rotor or brake drum. it could cause the wheel to work loose as the vehicle is driven, resulting in a loss of control and an injury accident. Never use heat to loosen a tight wheel. It can shorten the life of the wheel, bolts or spindle and bearings. Wheel nuts must be tightened in sequence and to the proper torque to avoid bending the wheel or rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Maintenance > Vehicle Lifting > Component Information > Service and Repair Vehicle Lifting: Service and Repair Vehicle Lift Points Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Compression Check > System Information > Specifications Compression Check: Specifications The lowest reading cylinder should not be less than 70% of the highest and no cylinder reading should be less than 689 kPa (100 psi). Perform compression test with engine at normal operating temperature, spark plugs removed and throttle wide open. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Camshaft, Engine > Component Information > Specifications > Camshaft Journal & Lifter Specs Camshaft: Specifications Camshaft Journal & Lifter Specs Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Camshaft Journal Diameter ................................................................................................................. ............................................................ 1.8677-1.8697 Camshaft Endplay .......................................... ................................................................................................................................................. 0.0040-0.0120 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Camshaft, Engine > Component Information > Specifications > Camshaft Journal & Lifter Specs > Page 1994 Camshaft: Specifications Camshaft Lift Specs Int. ........................................................................................................................................................ .......................................................................... .279 Exh. .................................................................. .............................................................................................................................................................. . .286 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Camshaft, Engine > Component Information > Specifications > Page 1995 Camshaft: Service and Repair Fig. 10 Camshaft Removal 1. Remove intake manifold as described under "Intake Manifold Service and Repair." 2. Remove oil pump drive and driveshaft. 3. Remove valve covers, rocker arms and push rods. Keep rocker arms and push rods in order so they can be installed in same locations. 4. Remove accessory drive belt(s), then remove upper fan shroud. 5. Remove radiator. 6. On models equipped with A/C, discharge refrigerant system and remove condenser. 7. On all models remove timing chain as described under "Timing Chain, Service and Repair. 8. Remove grille. 9. Remove valve lifters. Keep valve lifters in order so they can be installed in same locations. 10. Install three 5/16-18 x 4 inch bolts in camshaft bolt holes, then carefully remove camshaft, Fig.10. 11. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Lifter / Lash Adjuster, Valve > Component Information > Service and Repair Lifter / Lash Adjuster: Service and Repair Fig. 8 Exploded View Of Hydraulic Valve Lifter Valve lifters can be lifted from their bores after removing rocker arms and push rods and intake manifold. Adjustable pliers with protected jaws may be used to remove lifters which are stuck due to carbon or varnish deposits. Fig.8. illustrates the type of valve lifter used. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Push Rod > Component Information > Service and Repair Push Rod: Service and Repair On engines that use push rods with a hardened insert at one end, the hardened end is identified by a color stripe and should always be installed toward the rocker arm during assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Rocker Arm Assembly > Component Information > Adjustments Rocker Arm Assembly: Adjustments Fig. 5 Valve Lash Adjustment Adjust valves, Fig.5, with engine at normal operating temperature. Rotate engine until No. 1 cylinder is in position to fire. Adjust exhaust valves 1-3-4-8 and intake valves 1-2-5-7. Crank engine one complete revolution, then adjust exhaust valves 2-5-6-7 and intake vales 3-4-6-8. On all engines, the following procedure, performed with the engine running, should only be performed if readjustment is required. 1. After engine has been warmed up to normal operating temperature, remove valve cover and install a new valve cover gasket. 2. With engine running at idle speed, back off valve rocker arm nut until rocker arm starts to clatter. 3. Turn rocker arm nut down slowly until clatter just stops. This is the zero lash position. 4. Turn nut down 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat additional 1/4 turns, pausing 10 seconds each time, until nut has been turned down the number of turns listed in "Valve Clearance Specifications chart from the zero lash position. This preload adjustment must be done slowly to allow lifter to adjust itself to prevent the possibility of interference between valve head and top of piston, which might result in internal damage and/or bent push rods. Noisy lifters should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Rocker Arm Assembly > Component Information > Service and Repair > Rocker Arm Rocker Arm Assembly: Service and Repair Rocker Arm When replacing rocker arms or rocker arm balls, bearing surfaces of rocker arms and balls should be coated with pre-lube part No. 3755008 or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Camshaft, Lifters and Push Rods > Rocker Arm Assembly > Component Information > Service and Repair > Rocker Arm > Page 2007 Rocker Arm Assembly: Service and Repair Rocker Arm Studs Replace Fig. 6 Rocker Arm Stud Removal Fig. 7 Rocker Arm Stud Installation If studs are loose in cylinder head, .003 inch or .013 inch oversize studs may be installed after reaming holes with a proper size reamer. 1. Remove old stud by placing a suitable spacer, Fig.6. over stud. Install nut and flat washer and remove stud by turning nut. 2. Ream hole for oversize stud. 3. Coat press-fit area of stud with rear axle lube. Then install new stud, Fig.7. If tool shown is used, it should bottom on the head. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Connecting Rod Bearing > Component Information > Service and Repair Connecting Rod Bearing: Service and Repair Connecting rod bearings are available in standard and undersizes of .001, .002, .010 and .020 inch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Connecting Rod, Engine > Component Information > Specifications Connecting Rod: Specifications Torque Specifications 1994 47 ft.lb 1995-1996 20 ft.lb then tighten each nut an additional 55 degrees Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Crankshaft Main Bearing > Component Information > Service and Repair Crankshaft Main Bearing: Service and Repair Main bearings are available in standard and undersizes of .001, .002, .009, .010 and .020 inch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Crankshaft, Engine > Component Information > Specifications > Main Bearing Torque Specifications Crankshaft: Specifications Main Bearing Caps Main Bearing Caps Torque Specifications 77 ft.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Crankshaft, Engine > Component Information > Specifications > Main Bearing Torque Specifications > Page 2022 Crankshaft: Specifications Crankshaft Dimensions Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Crankshaft Standard Journal Diameter Main Bearing ....................................................................................................................................... .................................................................. [05] Crank Pin ................................................................... ........................................................................................................................... 2.0978-2.0998 Out of Round All [01] ........................................................................................................................... .................................................................. 0.001 Taper All [01] .......................................................... ................................................................................................................................................ 0.001 Bearing Clearance Main Bearings ...................................................................................................................................... ...................................................................... [07] Connecting Rod Bearings ...................................... ................................................................................................................................... 0.0013-0.0035 Thrust Bearing Clearance .................................................................................................................... ........................................................ 0.001-0.007 Connecting Rod Side Clearance ......................................................................................................... ................................................................ 0.006-0.014 [01] Maximum. [05] Diameter No. 1, 2.4484-2.4493 inches] diameter No. 2, 3 & 4, 2.4481-2.4490 inches] journal No. 5, 2.4479-2.4488 inches. [07] Journal No. 1, 0.0010-0.0015 inch] journal No. 2, 3 & 4, .0011-.0025 inch] journal No. 5, 0.0017-0.0035 inch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Harmonic Balancer Crankshaft Pulley > Component Information > Service and Repair Harmonic Balancer - Crankshaft Pulley: Service and Repair CRANKSHAFT BALANCER AND HUB Tool Required, or equivalent: J39046 Crankshaft Hub Remover/Installer 5.7L Shown 4.3L Similar REMOVAL Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Harmonic Balancer Crankshaft Pulley > Component Information > Service and Repair > Page 2026 1. Raise and suitably support the vehicle. 2. Remove the accessory drive belt. Remove the crankshaft balancer bolts. 3. Remove the crankshaft balancer. 4. Match mark the crankshaft hub to the engine front cover. 5. Do not crank the engine over after match marking the crankshaft hub and the engine front cover. Rotating the crankshaft will cause misalignment of the crankshaft balancer, to the crankshaft, possibly resulting in engine imbalance. 6. Remove the crankshaft hub bolt and the crankshaft washer. 7. Remove the crankshaft hub using the Crankshaft Hub Remover/Installer. INSTALLATION 1. Install the crankshaft hub using the Crankshaft Hub Remover/Installer. 2. If the engine should accidentally be cranked over after match marking the hub and the engine front cover, install the crankshaft hub as follows: a. Set the number 1 piston to the top dead center. b. While viewing the crankshaft from the front. Verify that the keyway of the reluctor ring is properly orientated with the key of the crankshaft. Also verify that the ring is completely seated against the crankshaft sprocket. c. Install the crankshaft hub with the cast arrow on the hub in the 12 o'clock position. 3. Install the crankshaft hub washer and the bolt. Tighten the crankshaft balancer hub bolt to 100 Nm (74 ft. lbs.). CAUTION: If the balancer is replaced, a new balance weight of the same size must be installed on the new balancer in the same hole locations as the old balancer. 4. Install the crankshaft balancer. 5. Install the crankshaft balancer bolts. Tighten the crankshaft balancer bolt to 85 Nm (63 ft. lbs.). 6. Install the accessory drive belt. 7. Lower the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Piston, Engine > Component Information > Specifications Piston: Specifications Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Piston Clearance ................................................................................................................................. ............................................................ 0.0007-0.0027 Piston Pin Diameter [01] ................................. ................................................................................................................................................ 0.9270-0.9271 Piston Pin To Piston Clearance ................................................................................... .................................................................................... 0.0004-0.0010 Piston Ring End Gap [02] Comp. .................................................................................................................................................. ..................................................................... 0.035 Oil ........................................................................ ..................................................................................................................................................... 0.065 Piston Ring Side Clearance Comp. .................................................................................................................................................. ....................................................... 0.0012-0.0042 Oil ........................................................................ ........................................................................................................................................... 0.002-0.008 [01] Pistons & pins are matched set & should be replaced as an assembly. [02] Maximum. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Piston, Engine > Component Information > Service and Repair > Oversize Availability Piston: Service and Repair Oversize Availability Pistons are available in standard and oversizes of .010 and .030 inch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Piston, Engine > Component Information > Service and Repair > Oversize Availability > Page 2032 Piston: Service and Repair Pistons & Rods Assemble Fig. 11 Piston & Rod Assembly Assemble pistons to connecting rods as shown in Fig. 11 Upon installation, measure the connecting rod side clearance using a suitable feeler gauge. Refer to SPECIFICATIONS/ENGINE REBUILDING Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Piston, Engine > Component Information > Service and Repair > Oversize Availability > Page 2033 SPECIFICATIONS for connecting rod side clearance. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Piston Pin, Engine > Component Information > Specifications Piston Pin: Specifications Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Piston Clearance ................................................................................................................................. ............................................................ 0.0007-0.0027 Piston Pin Diameter [01] ................................. ................................................................................................................................................ 0.9270-0.9271 Piston Pin To Piston Clearance ................................................................................... .................................................................................... 0.0004-0.0010 Piston Ring End Gap [02] Comp. .................................................................................................................................................. ..................................................................... 0.035 Oil ........................................................................ ..................................................................................................................................................... 0.065 Piston Ring Side Clearance Comp. .................................................................................................................................................. ....................................................... 0.0012-0.0042 Oil ........................................................................ ........................................................................................................................................... 0.002-0.008 [01] Pistons & pins are matched set & should be replaced as an assembly. [02] Maximum. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Piston Ring, Engine > Component Information > Specifications Piston Ring: Specifications Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Piston Clearance ................................................................................................................................. ............................................................ 0.0007-0.0027 Piston Pin Diameter [01] ................................. ................................................................................................................................................ 0.9270-0.9271 Piston Pin To Piston Clearance ................................................................................... .................................................................................... 0.0004-0.0010 Piston Ring End Gap [02] Comp. .................................................................................................................................................. ..................................................................... 0.035 Oil ........................................................................ ..................................................................................................................................................... 0.065 Piston Ring Side Clearance Comp. .................................................................................................................................................. ....................................................... 0.0012-0.0042 Oil ........................................................................ ........................................................................................................................................... 0.002-0.008 [01] Pistons & pins are matched set & should be replaced as an assembly. [02] Maximum. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Block Assembly > Piston Ring, Engine > Component Information > Specifications > Page 2040 Piston Ring: Service and Repair Piston rings are available in standard and oversizes of .030 inch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve Clearance > System Information > Specifications Valve Clearance: Specifications VALVE LASH Turn rocker arm stud nut until all lash is eliminated (zero lash), then tighten nut additional turn in 1/4 turn increments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve Clearance > System Information > Specifications > Page 2045 Valve Clearance: Adjustments Fig. 5 Valve Lash Adjustment Adjust valves, Fig.5, with engine at normal operating temperature. Rotate engine until No. 1 cylinder is in position to fire. Adjust exhaust valves 1-3-4-8 and intake valves 1-2-5-7. Crank engine one complete revolution, then adjust exhaust valves 2-5-6-7 and intake vales 3-4-6-8. On all engines, the following procedure, performed with the engine running, should only be performed if readjustment is required. 1. After engine has been warmed up to normal operating temperature, remove valve cover and install a new valve cover gasket. 2. With engine running at idle speed, back off valve rocker arm nut until rocker arm starts to clatter. 3. Turn rocker arm nut down slowly until clatter just stops. This is the zero lash position. 4. Turn nut down 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat additional 1/4 turns, pausing 10 seconds each time, until nut has been turned down the number of turns listed in "Valve Clearance Specifications chart from the zero lash position. This preload adjustment must be done slowly to allow lifter to adjust itself to prevent the possibility of interference between valve head and top of piston, which might result in internal damage and/or bent push rods. Noisy lifters should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Fuel Pressure Release > System Information > Service and Repair Fuel Pressure Release: Service and Repair WARNING: - To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing fuel system components. - After relieving the fuel system pressure a small amount of fuel may be released when servicing fuel lines or connections. In order to reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting, to catch any fuel that may leak out. Place the shop towel in an approved container when the disconnect is complete. Fuel Pressure Test Port PROCEDURE: 1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine. 2. Loosen the fuel filler cap to relieve tank pressure. 3. Connect the J 34730-1 fuel pressure gauge to the fuel pressure connection on the fuel rail. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage. 4. Install a bleed hose into an approved container and open the valve slowly to relieve system pressure. Fuel connections are now safe for servicing. 5. Drain any fuel remaining in the gauge into an approved container. NOTE: After repairs are complete, tighten the fuel cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Rocker Arm Assembly > Component Information > Adjustments Rocker Arm Assembly: Adjustments Fig. 5 Valve Lash Adjustment Adjust valves, Fig.5, with engine at normal operating temperature. Rotate engine until No. 1 cylinder is in position to fire. Adjust exhaust valves 1-3-4-8 and intake valves 1-2-5-7. Crank engine one complete revolution, then adjust exhaust valves 2-5-6-7 and intake vales 3-4-6-8. On all engines, the following procedure, performed with the engine running, should only be performed if readjustment is required. 1. After engine has been warmed up to normal operating temperature, remove valve cover and install a new valve cover gasket. 2. With engine running at idle speed, back off valve rocker arm nut until rocker arm starts to clatter. 3. Turn rocker arm nut down slowly until clatter just stops. This is the zero lash position. 4. Turn nut down 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat additional 1/4 turns, pausing 10 seconds each time, until nut has been turned down the number of turns listed in "Valve Clearance Specifications chart from the zero lash position. This preload adjustment must be done slowly to allow lifter to adjust itself to prevent the possibility of interference between valve head and top of piston, which might result in internal damage and/or bent push rods. Noisy lifters should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Rocker Arm Assembly > Component Information > Service and Repair > Rocker Arm Rocker Arm Assembly: Service and Repair Rocker Arm When replacing rocker arms or rocker arm balls, bearing surfaces of rocker arms and balls should be coated with pre-lube part No. 3755008 or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Rocker Arm Assembly > Component Information > Service and Repair > Rocker Arm > Page 2054 Rocker Arm Assembly: Service and Repair Rocker Arm Studs Replace Fig. 6 Rocker Arm Stud Removal Fig. 7 Rocker Arm Stud Installation If studs are loose in cylinder head, .003 inch or .013 inch oversize studs may be installed after reaming holes with a proper size reamer. 1. Remove old stud by placing a suitable spacer, Fig.6. over stud. Install nut and flat washer and remove stud by turning nut. 2. Ream hole for oversize stud. 3. Coat press-fit area of stud with rear axle lube. Then install new stud, Fig.7. If tool shown is used, it should bottom on the head. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve Guide > Component Information > Specifications Valve Guide: Specifications Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Valve Guides Stem To Guide Clearance Intake ................................................................................................................................................... ................................................. 0.0009-0.0037 Exhaust ..................................................................... ............................................................................................................................ 0.0009-0.0047 Valve Seats Seat Angle ........................................................................................................................................... ................................................................... 46deg. Seat Width Intake ................................................................................................................................................... ..................................................... 0.030-0.065 Exhaust ..................................................................... ................................................................................................................................ 0.060-0.098 Runout ................................................................................................................................................. .......................................................................... 0.002 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve Guide > Component Information > Specifications > Page 2058 Valve Guide: Service and Repair On all engines valves operate in guide holes bored in the head. If clearance becomes excessive, use the next oversize valve and ream the bore to fit. Valves with oversize stems are available in .003, .015 and .030 inch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve Seat > Component Information > Specifications Valve Seat: Specifications Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Valve Guides Stem To Guide Clearance Intake ................................................................................................................................................... ................................................. 0.0009-0.0037 Exhaust ..................................................................... ............................................................................................................................ 0.0009-0.0047 Valve Seats Seat Angle ........................................................................................................................................... ................................................................... 46deg. Seat Width Intake ................................................................................................................................................... ..................................................... 0.030-0.065 Exhaust ..................................................................... ................................................................................................................................ 0.060-0.098 Runout ................................................................................................................................................. .......................................................................... 0.002 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve Spring > Component Information > Specifications Valve Spring: Specifications Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Free Length ......................................................................................................................................... ............................................................................ 2.02 Installed Height ............................................... .............................................................................................................................................................. .... 1.7 Seated Pressure Pounds @ Inches ......................................................................................... ........................................................................... 76-84 @ 1.70 Comp. Pressure Pounds @ Inches .. .............................................................................................................................................................. 187-203 @ 1.27 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve, Intake/Exhaust > Component Information > Specifications > Valve Lift Specifications Valve: Specifications Valve Lift Specifications Int. ........................................................................................................................................................ .......................................................................... .418 Exh. .................................................................. .............................................................................................................................................................. . .430 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve, Intake/Exhaust > Component Information > Specifications > Valve Lift Specifications > Page 2069 Valve: Specifications Valve Clearance Specifications Valve Lash 1 Turn .................................................................................................................................................. ............................................................................. [1] [1] Turn rocker arm stud nut until all lash is eliminated (zero lash), then tighten nut additional turn in 1/4 turn increments. Refer to Valve Adjustment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve, Intake/Exhaust > Component Information > Specifications > Page 2070 Valve: Locations FRONT TO REAR All.................E-I-I-E-E-I-I-E Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Cylinder Head Assembly > Valve, Intake/Exhaust > Component Information > Specifications > Page 2071 Valve: Service and Repair Engine Liter/VIN .................................................................................................................................. .................................................................... 5.7L/P All Measurements Given In Inches Unless Otherwise Specified Valve Lash Intake ................................................................................................................................................... ....................................................................... [05] Exhaust ................................................................. ...................................................................................................................................................... [05] Face Angle .......................................................................................................................................... ......................................................................... 45deg. Margin ............................................................ .............................................................................................................................................................. .. [01] [01] Minimum. [05] Zero lash plus or minus 1 1/4 turns. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics Drive Belt: Technical Service Bulletins Engine - Drive Belt Misalignment Diagnostics INFORMATION Bulletin No.: 08-06-01-008A Date: July 27, 2009 Subject: Diagnosing Accessory Drive Belt / Serpentine Belt Noise and Availability and Use of Kent-Moore EN-49228 Laser Alignment Tool - Drive Belt Models: 2010 and Prior GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 Vehicles 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add a model year and update the Tool Information. Please discard Corporate Bulletin Number 08-06-01-008 (Section 06 - Engine). Background Several aftermarket companies offer laser alignment tools for accessory drive systems that can be very helpful in eliminating drive belt noise as a result of misaligned pulleys. Typically pricing ranges from $160 - $200. EN-49228 Laser Alignment Tool - Drive Belt The GM Tool program has now made available a competitive, simple to use and time-saving laser tool to assist in achieving precise alignment of the drive belt pulleys. This optional tool removes the guesswork from proper pulley alignment and may serve to reduce comebacks from: - Drive Belt Noise - Accelerated Drive Belt Wear - Drive Belt Slippage Instructions The instructions below are specific only to the truck Gen IV V-8 family of engines. These instructions are only for illustrative purposes to show how the tool may be used. Universal instructions are included in the box with the Laser Alignment Tool - Drive Belt. Caution - Do not look directly into the beam projected from the laser. - Use caution when shining the laser on highly polished or reflective surfaces. Laser safety glasses help reduce laser beam glare in many circumstances. - Always use laser safety glasses when using the laser. Laser safety glasses are not designed to protect eyes from direct laser exposure. 1. Observe and mark the serpentine belt orientation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics > Page 2077 2. Remove the serpentine belt from the accessory drive system. 3. Install the tool onto the power steering pulley. Position the legs of the tool into the outer grooves of the pulley, farthest from the front of the engine. 4. Install the retaining cord around the pulley and to the legs of the tool. 5. Put on the laser safety glasses provided with the tool. 6. Depress the switch on the rear of the tool to activate the light beam. 7. Rotate the power steering pulley as required to project the light beam onto the crankshaft balancer pulley grooves. 8. Inspect for proper power steering pulley alignment. - If the laser beam projects onto the second rib or raised area (1), the pulleys are aligned properly. - If the laser beam projects more than one-quarter rib 0.9 mm (0.035 in) mis-alignment, adjust the position of the power steering pulley as required. - Refer to SI for Power Steering Pulley Removal and Installation procedures. 9. Install the serpentine belt to the accessory drive system in the original orientation. 10. Operate the vehicle and verify that the belt noise concern is no longer present. Tool Information Please visit the GM service tool website for pricing information or to place your order for this tool. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics > Page 2078 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt > Component Information > Technical Service Bulletins > Engine - Drive Belt Misalignment Diagnostics > Page 2079 Drive Belt: Technical Service Bulletins Engine - Serpentine Drive Belt Wear Information Bulletin No.: 04-06-01-013 Date: April 29, 2004 INFORMATION Subject: Information on Serpentine Belt Wear Models: 2004 and Prior Passenger Cars and Trucks 2003-2004 and Prior HUMMER H2 All current GM vehicles designed and manufactured in North America were assembled with serpentine belts that are made with an EPDM material and should last the life of the vehicle. It is extremely rare to observe any cracks in EPDM belts and it is not expected that they will require maintenance before 10 years or 240,000 km (150,000 mi) of use. Older style belts, which were manufactured with a chloroprene compound, may exhibit cracks depending on age. However, the onset of cracking typically signals that the belt is only about halfway through its usable life. A good rule of thumb for chloroprene-based belts is that if cracks are observed 3 mm (1/8 in) apart, ALL AROUND THE BELT, the belt may be reaching the end of its serviceable life and should be considered a candidate for changing. Small cracks spaced at greater intervals should not be considered as indicative that the belt needs changing. Any belt that exhibits chunking should be replaced. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt > Component Information > Specifications > Serpentine Belt Tension Specification Drive Belt: Specifications Serpentine Belt Tension Specification Engines equipped with serpentine belts have an automatic tensioner. No adjustment of this is necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt > Component Information > Specifications > Serpentine Belt Tension Specification > Page 2082 Drive Belt: Specifications Air Conditioning Belt Tension Specification New ..................................................................................................................................................... ............................................................... 105-125 Lbs Used .................................................................................................................................................... ............................................................... 105-125 Lbs Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt > Component Information > Specifications > Page 2083 Drive Belt: Service and Repair Fig. 16 Serpentine Drive Belt Routing SERPENTINE DRIVE BELT BELT ROUTING Refer to Fig.16. for serpentine belt routing diagrams. BELT REPLACEMENT 1. Disconnect battery ground cable. 2. On models with mechanical cooling fan, proceed as follows: a. Rotate mechanical cooling fan tensioner pulley clockwise using a suitable 13 mm wrench while sliding belt from tensioner pulley. b. Remove fan belt from pulleys. c. Remove radiator outlet nuts at air conditioning compressor. 3. On all models, rotate tensioner pulley clockwise using a suitable 9/16 offset wrench while sliding belt from tensioner, then remove serpentine drive belt. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Drive Belt Tensioner > Component Information > Service and Repair Drive Belt Tensioner: Service and Repair 1. Disconnect battery ground cable. 2. Remove serpentine belt as outlined under Drive belts Service and Repair. 3. Remove belt tensioner attaching bolt, then belt tensioner. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Engine Mount > Component Information > Service and Repair Engine Mount: Service and Repair Fig. 1 Engine & Transmission Mounting 1. Remove mount retaining bolt from below frame mounting bracket, Fig. 1. 2. Raise front of engine and remove mount to engine bolts and mount. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Drive Belts, Mounts, Brackets and Accessories > Engine Mount > Component Information > Service and Repair > Page 2090 3. On all models, raise engine only enough to provide sufficient clearance for mount removal. Check for interference between rear of engine and cowl panel which could result in distributor damage. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Engine Oil Pressure > Component Information > Specifications Engine Oil Pressure: Specifications Normal Oil Pressure, psi ................................................. Minimum w/ engine hot, 6 psi. @ 1000 RPM; 18 psi. @ 2000 RPM; 24 psi. @ 4000 RPM. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Engine Oil > Component Information > Technical Service Bulletins > Engine - GM dexos 1 and dexos 2(R) Oil Specifications Engine Oil: Technical Service Bulletins Engine - GM dexos 1 and dexos 2(R) Oil Specifications INFORMATION Bulletin No.: 11-00-90-001 Date: March 14, 2011 Subject: Global Information for GM dexos1(TM) and GM dexos2(TM) Engine Oil Specifications for Spark Ignited and Diesel Engines, Available Licensed Brands, and Service Fill for Adding or Complete Oil Change Models: 2012 and Prior GM Passenger Cars and Trucks Excluding All Vehicles Equipped with Duramax(TM) Diesel Engines GM dexos 1(TM) Information Center Website Refer to the following General Motors website for dexos 1(TM) information about the different licensed brands that are currently available: http://www.gmdexos.com GM dexos 1(TM) Engine Oil Trademark and Icons The dexos(TM) specification and trademarks are exclusive to General Motors, LLC. Only those oils displaying the dexos‹›(TM) trademark and icon on the front label meet the demanding performance requirements and stringent quality standards set forth in the dexos‹›(TM) specification. Look on the front label for any of the logos shown above to identify an authorized, licensed dexos 1(TM) engine oil. GM dexos 1(TM) Engine Oil Specification Important General Motors dexos 1(TM) engine oil specification replaces the previous General Motors specifications GM6094M, GM4718M and GM-LL-A-025 for most GM gasoline engines. The oil specified for use in GM passenger cars and trucks, PRIOR to the 2011 model year remains acceptable for those previous vehicles. However, dexos 1(TM) is backward compatible and can be used in those older vehicles. In North America, starting with the 2011 model year, GM introduced dexos 1(TM) certified engine oil as a factory fill and service fill for gasoline engines. The reasons for the new engine oil specification are as follows: - To meet environmental goals such as increasing fuel efficiency and reducing engine emissions. - To promote long engine life. - To minimize the number of engine oil changes in order to help meet the goal of lessening the industry's overall dependence on crude oil. dexos 1(TM) is a GM-developed engine oil specification that has been designed to provide the following benefits: - Further improve fuel economy, to meet future corporate average fuel economy (CAFE) requirements and fuel economy retention by allowing the oil to maintain its fuel economy benefits throughout the life of the oil. - More robust formulations for added engine protection and aeration performance. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Engine Oil > Component Information > Technical Service Bulletins > Engine - GM dexos 1 and dexos 2(R) Oil Specifications > Page 2099 - Support the GM Oil Life System, thereby minimizing the replacement of engine oil, before its life has been depleted. - Reduce the duplication of requirements for a large number of internal GM engine oil specifications. International Lubricants Standardization and Approval Committee (ILSAC) GF-5 Standard In addition to GM dexos 1(TM), a new International Lubricants Standardization and Approval Committee (ILSAC) standard called GF-5, was introduced in October 2010. - There will be a corresponding API category, called: SN Resource Conserving. The current GF-4 standard was put in place in 2004 and will become obsolete in October 2011. Similar to dexos 1(TM), the GF-5 standard will use a new fuel economy test, Sequence VID, which demands a statistically significant increase in fuel economy versus the Sequence VIB test that was used for GF-4. - It is expected that all dexos 1(TM) approved oils will be capable of meeting the GF-5 standard. However, not all GF-5 engine oils will be capable of meeting the dexos 1(TM) specification. - Like dexos(TM), the new ILSAC GF-5 standard will call for more sophisticated additives. The API will begin licensing marketers during October 2010, to produce and distribute GF-5 certified products, which are expected to include SAE 0W-20, 0W-30, 5W-20, 5W-30 and 10W-30 oils. Corporate Average Fuel Economy (CAFE) Requirements Effect on Fuel Economy Since CAFE standards were first introduced in 1974, the fuel economy of cars has more than doubled, while the fuel economy of light trucks has increased by more than 50 percent. Proposed CAFE standards call for a continuation of increased fuel economy in new cars and trucks. To meet these future requirements, all aspects of vehicle operation are being looked at more critically than ever before. New technology being introduced in GM vehicles designed to increase vehicle efficiency and fuel economy include direct injection, cam phasing, turbocharging and active fuel management (AFM). The demands of these new technologies on engine oil also are taken into consideration when determining new oil specifications. AFM for example can help to achieve improved fuel economy. However alternately deactivating and activating the cylinders by not allowing the intake and exhaust valves to open contributes to additional stress on the engine oil. Another industry trend for meeting tough fuel economy mandates has been a shift toward lower viscosity oils. dexos 1(TM) will eventually be offered in several viscosity grades in accordance with engine needs: SAE 0W-20, 5W-20, 0W-30 and 5W-30. Using the right viscosity grade oil is critical for proper engine performance. Always refer to the Maintenance section of a vehicle Owner Manual for the proper viscosity grade for the engine being serviced. GM Oil Life System in Conjunction With dexos (TM) Supports Extended Oil Change Intervals To help conserve oil while maintaining engine protection, many GM vehicles are equipped with the GM Oil Life System. This system can provide oil change intervals that exceed the traditional 3,000 mile (4,830 km) recommendation. The dexos (TM) specification, with its requirements for improved oil robustness, compliments the GM Oil Life System by supporting extended oil change intervals over the lifetime of a vehicle. If all GM customers with GM Oil Life System equipped vehicles would use the system as intended, GM estimates that more than 100 million gallons of oil could be saved annually. GM dexos 2(TM) Information Center Website Refer to the following General Motors website for dexos 2(TM) information about the different licensed brands that are currently available: http://www.gmdexos.com GM dexos 2(TM) Engine Oil Trademark and Icons Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Engine Oil > Component Information > Technical Service Bulletins > Engine - GM dexos 1 and dexos 2(R) Oil Specifications > Page 2100 The dexos (TM) specification and trademarks are exclusive to General Motors, LLC. Only those oils displaying the dexos (TM) trademark and icon on the front label meet the demanding performance requirements and stringent quality standards set forth in the dexos (TM)specification. Look on the front label for any of the logos shown above to identify an authorized, licensed dexos 2(TM) engine oil. GM dexos 2(TM) Engine Oil Specification - dexos 2(TM) is approved and recommended by GM for use in Europe starting in model year 2010 vehicles, regardless of where the vehicle was manufactured. - dexos 2(TM) is the recommended service fill oil for European gasoline engines. Important The Duramax(TM) diesel engine is the exception and requires lubricants meeting specification CJ-4. - dexos 2(TM) is the recommended service fill oil for European light-duty diesel engines and replaces GM-LL-B-025 and GM-LL-A-025. - dexos 2(TM) protects diesel engines from harmful soot deposits and is designed with limits on certain chemical components to prolong catalyst life and protect expensive emission reduction systems. It is a robust oil, resisting degradation between oil changes and maintaining optimum performance longer. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Engine Oil > Component Information > Specifications > Capacity Specifications Engine Oil: Capacity Specifications Fluid Type ............................................................................................................................................ .................................................. API service SH/SG Capacity Without filter change ............................................................................................................................ ................................................. 3.8 liters (4.0 qt) With filter change .................................................... .............................................................................................................................. 4.7 liters (5.0 qt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Filter, Engine > Component Information > Technical Service Bulletins > Engine - Noise/Damage Oil Filter Application Importance Oil Filter: Technical Service Bulletins Engine - Noise/Damage Oil Filter Application Importance INFORMATION Bulletin No.: 07-06-01-016B Date: July 27, 2009 Subject: Information on Internal Engine Noise or Damage After Oil Filter Replacement Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being updated to add model years. Please discard Corporate Bulletin Number 07-06-01-016A (Section 06 - Engine/Propulsion System). Important Engine damage that is the result of an incorrect or improperly installed engine oil filter is not a warrantable claim. The best way to avoid oil filter quality concerns is to purchase ACDelco(R) oil filters directly from GMSPO. Oil filter misapplication may cause abnormal engine noise or internal damage. Always utilize the most recent parts information to ensure the correct part number filter is installed when replacing oil filters. Do not rely on physical dimensions alone. Counterfeit copies of name brand parts have been discovered in some aftermarket parts systems. Always ensure the parts you install are from a trusted source. Improper oil filter installation may result in catastrophic engine damage. Refer to the appropriate Service Information (SI) installation instructions when replacing any oil filter and pay particular attention to procedures for proper cartridge filter element alignment. If the diagnostics in SI (Engine Mechanical) lead to the oil filter as the cause of the internal engine noise or damage, dealers should submit a field product report. Refer to Corporate Bulletin Number 02-00-89-002I (Information for Dealers on How to Submit a Field Product Report). Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Warning Indicator > Component Information > Description and Operation Oil Level Warning Indicator: Description and Operation DESCRIPTION This lamp illuminates to warn the driver that the engine oil level is low. When the ignition switch is first moved to Run, the oil level indicator lights for about 1 1/2 seconds as a bulb check. The oil level detection circuit has two internal timers. The first timer records the amount of time the ignition has been Off. The second timer records the amount of time the ignition has been On before the ignition was shut Off. The instrument cluster uses this information to determine if the engine has been sitting long enough for the oil to have returned to the oil pan. OPERATION The oil level monitoring circuits will check the oil level switch under the following conditions: 1. Ignition has been turned Off for more than 30 minutes. 2. Ignition has been Off for at least three minutes after ignition has been On for at least 12 minutes. If the oil level is low (oil level switch open), the "Check Oil" indicator will be turned On for the remainder of the ignition cycle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator Inoperative W/Oil Level Low Fig. 99 Chart 8: Low Oil Level Indicator Inoperative W/Oil Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low > Page 2112 Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator On w/Oil Level OK Fig. 98 Chart 7: Low Oil Level Indicator On W/Oil Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Locations Engine, Left Side Lower Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions Oil Level Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2118 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2119 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2120 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2121 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2122 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2123 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2124 Oil Level Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2125 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2126 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2127 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2128 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2129 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2130 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2131 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2132 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2133 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2134 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2135 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2136 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2137 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2138 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2139 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2140 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2141 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2142 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2143 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2144 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2145 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2146 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2147 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2148 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pan, Engine > Component Information > Service and Repair Oil Pan: Service and Repair Fig. 14 Oil Pan & Gasket Assembly 1. Disconnect battery ground cable, then remove air cleaner, resonator and air intake duct. 2. Remove radiator upper fan shroud if equipped with a mechanical fan. 2. Disconnect windshield wiper motor electrical connector. 3. Raise and support vehicle, then drain engine oil. 4. Disconnect oil level sensor connector, then remove oil level sensor. 5. Remove warm up three-way catalytic converters from exhaust manifolds, then catalytic converter support-to-transmission bolts/screws and Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pan, Engine > Component Information > Service and Repair > Page 2152 washers. 6. Remove engine oil filter adapter, then disconnect transmission fluid cooler lines from clip at oil pan. 7. Remove starter, then converter cover bolt/screws and cover. 8. Rotate crankshaft until arrow on crankshaft balancer is pointing straight down (six o'clock). 9. Remove engine mount through-bolts/screws and nuts, then raise engine with jacking fixture. 10. Remove oil pan bolts, screws, studs & nuts, then oil pan, reinforcements and gaskets Fig. 14 11. Reverse procedure to install. Apply a small quantity of sealer part No. 1052914 or equivalent to front cover and engine block junction and rear seal retainer and engine block junction. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Gauge > Component Information > Description and Operation Oil Pressure Gauge: Description and Operation DESCRIPTION This oil pressure indicating system incorporates an instrument voltage regulator, electrical oil pressure gauge and a sending unit which are connected in series. The sending unit consists of a diaphragm, contact and a variable resistor. OPERATION As oil pressure increases or decreases, the diaphragm actuated the contact on the variable resistor, in turn controlling current flow through the gauge. When oil pressure is low, the resistance of the variable resistor is high, restricting current flow to the gauge, in turn indicating low oil pressure. As oil pressure increases, the resistance of the variable resistor is lowered, permitting an increased current flow to the gauge, resulting in an increased gauge reading. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Gauge > Component Information > Description and Operation > Page 2156 Oil Pressure Gauge: Service and Repair Disconnect the oil pressure gauge lead from the sending unit, connect a 12 volt test lamp between the gauge lead and the ground and turn ignition on. If test lamp flashes, the instrument voltage regulator is functioning properly and the gauge circuit is not broken. If the test lamp remains lit, the instrument voltage regulator is defective and must be replaced. If the test lamp does not light, check the instrument voltage regulator for proper ground or an open circuit. Also, check for an open in the instrument voltage regulator to oil pressure gauge wire or in the gauge itself. If test lamp flashes and gauge is not accurate, the gauge may be out of calibration, requiring replacement. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Sender > Component Information > Locations Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Specifications Oil Pressure Switch (For Fuel Pump): Specifications Fuel Pump Switch and Engine Oil Pressure Sensor ................................................................................................................................... 12 Nm (106 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch > Page 2165 Oil Pressure Switch (For Fuel Pump): Locations Oil Pressure Sensor/Fuel Pump Switch Fuel Pump - Oil Pressure Switch The sensor is threaded into a TEE fitting at the rear of the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions Oil Pressure Switch (For Fuel Pump): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2168 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2169 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2170 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2171 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2172 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2173 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2174 Oil Pressure Switch (For Fuel Pump): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2175 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2176 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2177 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2178 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2179 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2180 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2181 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2182 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2183 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2184 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2185 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2186 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2187 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2188 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2189 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2190 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2191 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2192 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2193 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2194 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2195 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2196 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2197 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2198 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2199 Fuel Pump Switch/Engine Oil Pressure Gage Sensor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2200 Fuel Pump Relay Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 2201 Oil Pressure Switch (For Fuel Pump): Description and Operation Fuel Pump - Oil Pressure Switch As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 2202 Oil Pressure Switch (For Fuel Pump): Service and Repair Fuel Pump - Oil Pressure Switch REMOVE OR DISCONNECT 1. Disconnect electrical connector. 2. Fuel pump switch and oil pressure sensor. INSTALL OR CONNECT 1. Fuel pump switch and oil pressure sensor. 2. Tighten to 12 Nm (106 lb in.) 3. Electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Pump, Engine > Engine Oil Pressure > Component Information > Specifications Engine Oil Pressure: Specifications Normal Oil Pressure, psi ................................................. Minimum w/ engine hot, 6 psi. @ 1000 RPM; 18 psi. @ 2000 RPM; 24 psi. @ 4000 RPM. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Engine Lubrication > Oil Level Sensor <--> [Oil Temperature Gauge] > Component Information > Testing and Inspection Oil Level Sensor: Testing and Inspection Check for a defective wire inside the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with the system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Intake Manifold > Component Information > Technical Service Bulletins > Engine - Intake Manifold Inspection/Replacement Intake Manifold: Technical Service Bulletins Engine - Intake Manifold Inspection/Replacement INFORMATION Bulletin No.: 00-06-01-026C Date: February 03, 2010 Subject: Intake Manifold Inspection/Replacement After Severe Internal Engine Damage Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to include additional model years. Please discard Corporate Bulletin Number 00-06-01-026B (Section 06 - Engine). When replacing an engine due to internal damage, extreme care should be taken when transferring the intake manifold to the new Goodwrench service engine long block. Internal damage may result in the potential discharge of internal engine component debris in the intake manifold via broken pistons and/or bent, broken, or missing intake valves. After removing the intake manifold from the engine, the technician should carefully inspect all of the cylinder head intake ports to see if the valve heads are still present and not bent. Usually when the valve heads are missing or sufficiently bent, internal engine component debris will be present to varying degrees in the intake port of the cylinder head. If this debris is present in any of the cylinder head intake ports, the intake manifold should be replaced. This replacement is required due to the complex inlet runner and plenum configuration of most of the intake manifolds, making thorough and complete component cleaning difficult and nearly impossible to verify complete removal of debris. Re-installation of an intake manifold removed from an engine with deposits of internal engine component debris may result in the ingestion of any remaining debris into the new Goodwrench service engine. This may cause damage or potential failure of the new service engine. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Intake Manifold > Component Information > Technical Service Bulletins > Engine - Intake Manifold Inspection/Replacement > Page 2214 Intake Manifold: Technical Service Bulletins Engine - Use of Wacker RTV Sealant for Intake Manifold File In Section: 6 - Engine Bulletin No.: 67-61-17A Date: August, 1996 Subject: Use of Wacker T-330 RTV Sealant (Pronounced Vaucker T) Models: 1990-96 Buick Road master, Estate Wagon 1990-96 Cadillac Fleetwood 1990-96 Chevrolet Camaro, Caprice, Corvette, Impala SS 1990-92 Oldsmobile Custom Cruiser 1990-96 Pontiac Firebird with 4.3L, 5.7L Engine (VINs W, P, 5, 8 - RPOs L99, L98, LT1, LT4) 1990-96 Chevrolet and GMC Light and Medium Duty Trucks with 4.3L, 5.0L, 5.7L, 6.0L, 7.0L, 7.4L Engines (VINs W, Z, E H, K, M, N, P, R - RPOs L35, LB4, L03, L05, LS0, LR0, L19, L30, L31) This bulletin is being revised to add further Chevrolet models. Please discard Corporate Bulletin Number 67-61-17 (Section 6 - Engine). When installing the intake manifold, use a 5 mm (1/4 in.) thick bead of Wacker T-330 RTV, P/N 12346192, on the front and rear sealing areas between Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Intake Manifold > Component Information > Technical Service Bulletins > Engine - Intake Manifold Inspection/Replacement > Page 2215 the engine block and intake manifold. See Figures 1 and 2. Wacker T-330 RTV has improved adhesive abilities, is oxygen sensor safe, and is noncorrosive to ferrous metals. Wacker T-330 RW cannot be used in coolant sealing surface areas. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Intake Manifold > Component Information > Specifications > Intake Manifold Torque and Sequence Intake Manifold: Specifications Intake Manifold Torque and Sequence INTAKE MANIFOLD TORQUE SPECIFICATION AND SEQUENCE Intake Manifold Bolt Tightening Sequence Intake Manifold Bolt/Screw and Stud First Pass ............................................................................................................................................. .......................................................... 8 Nm (71 lb in) Final Pass ............................................................................................................................................ ......................................................... 48 Nm (35 lb ft) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Intake Manifold > Component Information > Specifications > Page 2218 Intake Manifold: Service and Repair These engines are equipped with a sequential multi-port fuel injection system. Fuel injector connectors must be positioned onto the correct fuel injectors or engine performance and exhaust emissions may be seriously affected. Fuel injector connectors are numbered to match the correct injector for that cylinder. 1. Disconnect battery ground cable, then drain coolant into suitable container(s). 2. Remove air cleaner resonator bracket nuts and resonator assembly by loosening clamp at air intake duct and sliding resonator assembly off studs. 3. Remove throttle body air duct. 4. Disconnect fuel injector wiring harness connectors. 5. Disconnect left and right wiring harness clips, then position aside. 6. Remove accelerator control cable bracket bolts/screws and bracket from throttle body. 7. Relieve fuel system pressure as outlined. 8. Disconnect fuel pipe connectors from fuel rail, then remove fuel rail bolts/screws. 9. Remove resonator bracket with canister purge solenoid attached. 10. Disconnect fuel pressure regulator vacuum tube, then remove fuel rail from intake manifold and position aside. 11. Disconnect vacuum and crankcase vent hoses. 12. Remove EGR control valve relay nut, then control valve relay. 13. Remove EGR valve pipe nuts, bolt/screw, pipe and gasket. Discard gasket. 14. Disconnect engine wiring harness and remove nuts at left front corner of intake manifold. 15. Disconnect coolant hoses from throttle body, then remove throttle body bolts/screws, throttle body and gasket. 16. Remove intake manifold bolts/screws and studs, then intake manifold and gaskets. Discard gaskets. 17. Reverse procedure to install, noting the following: a. Ensure surfaces are clean and dry, then apply a 3/16 bead of RTV sealer to front and rear of engine block. Extend bead approximately 1/2 inch up each cylinder head. b. Install manifold and retaining bolts, ensuring areas between case ridges and manifold are completely sealed. Intake Manifold Bolt Tightening Sequence c. Tighten manifold bolts to specifications in sequence shown in Fig. 2. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Lamps and Indicators - Engine > Oil Level Warning Indicator > Component Information > Description and Operation Oil Level Warning Indicator: Description and Operation DESCRIPTION This lamp illuminates to warn the driver that the engine oil level is low. When the ignition switch is first moved to Run, the oil level indicator lights for about 1 1/2 seconds as a bulb check. The oil level detection circuit has two internal timers. The first timer records the amount of time the ignition has been Off. The second timer records the amount of time the ignition has been On before the ignition was shut Off. The instrument cluster uses this information to determine if the engine has been sitting long enough for the oil to have returned to the oil pan. OPERATION The oil level monitoring circuits will check the oil level switch under the following conditions: 1. Ignition has been turned Off for more than 30 minutes. 2. Ignition has been Off for at least three minutes after ignition has been On for at least 12 minutes. If the oil level is low (oil level switch open), the "Check Oil" indicator will be turned On for the remainder of the ignition cycle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Lamps and Indicators - Engine > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator Inoperative W/Oil Level Low Fig. 99 Chart 8: Low Oil Level Indicator Inoperative W/Oil Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Lamps and Indicators - Engine > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low > Page 2225 Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator On w/Oil Level OK Fig. 98 Chart 7: Low Oil Level Indicator On W/Oil Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Lamps and Indicators - Engine > Oil Pressure Gauge > Component Information > Description and Operation Oil Pressure Gauge: Description and Operation DESCRIPTION This oil pressure indicating system incorporates an instrument voltage regulator, electrical oil pressure gauge and a sending unit which are connected in series. The sending unit consists of a diaphragm, contact and a variable resistor. OPERATION As oil pressure increases or decreases, the diaphragm actuated the contact on the variable resistor, in turn controlling current flow through the gauge. When oil pressure is low, the resistance of the variable resistor is high, restricting current flow to the gauge, in turn indicating low oil pressure. As oil pressure increases, the resistance of the variable resistor is lowered, permitting an increased current flow to the gauge, resulting in an increased gauge reading. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Lamps and Indicators - Engine > Oil Pressure Gauge > Component Information > Description and Operation > Page 2229 Oil Pressure Gauge: Service and Repair Disconnect the oil pressure gauge lead from the sending unit, connect a 12 volt test lamp between the gauge lead and the ground and turn ignition on. If test lamp flashes, the instrument voltage regulator is functioning properly and the gauge circuit is not broken. If the test lamp remains lit, the instrument voltage regulator is defective and must be replaced. If the test lamp does not light, check the instrument voltage regulator for proper ground or an open circuit. Also, check for an open in the instrument voltage regulator to oil pressure gauge wire or in the gauge itself. If test lamp flashes and gauge is not accurate, the gauge may be out of calibration, requiring replacement. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Lamps and Indicators - Engine > Oil Level Sensor <--> [Oil Temperature Gauge] > Component Information > Testing and Inspection Oil Level Sensor: Testing and Inspection Check for a defective wire inside the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with the system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Seals and Gaskets, Engine > Crankshaft Main Bearing Seal > Component Information > Service and Repair Crankshaft Main Bearing Seal: Service and Repair Fig. 12 Crankshaft Rear Oil Seal Retainer Notch Locations Fig. 13 Crankshaft Rear Oil Seal Installation These engines are equipped with a one-piece, lip type seal mounted in a separate seal retainer. Seal replacement requires removal of the transmission. 1. Raise and support vehicle, then remove transmission and flywheel. 2. Pry seal from retainer, inserting screwdriver in notches provided in seal retainer, Fig.12. 3. Lubricate inner and outer diameters of replacement seal with engine oil, then mount seal on tool No. J-35621, or equivalent, Fig.13. 4. Mount seal installer tool No. J-35621, or equivalent, on rear of crankshaft, tightening screws snugly to ensure seal will be installed squarely on crankshaft. 5. Tighten wing nut on tool until it bottoms, then remove tool from crankshaft. 6. Reverse remaining removal steps to complete installation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Locations Engine, Left Side Lower Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions Oil Level Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2243 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2244 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2245 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2246 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2247 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2248 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2249 Oil Level Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2250 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2251 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2252 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2253 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2254 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2255 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2256 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2257 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2258 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2259 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2260 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2261 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2262 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2263 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2264 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2265 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2266 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2267 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2268 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2269 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2270 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2271 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2272 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Level Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2273 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Sender > Component Information > Locations Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Specifications Oil Pressure Switch (For Fuel Pump): Specifications Fuel Pump Switch and Engine Oil Pressure Sensor ................................................................................................................................... 12 Nm (106 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch > Page 2282 Oil Pressure Switch (For Fuel Pump): Locations Oil Pressure Sensor/Fuel Pump Switch Fuel Pump - Oil Pressure Switch The sensor is threaded into a TEE fitting at the rear of the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions Oil Pressure Switch (For Fuel Pump): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2285 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2286 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2287 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2288 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2289 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2290 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2291 Oil Pressure Switch (For Fuel Pump): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2292 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2293 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2294 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2295 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2296 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2297 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2298 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2299 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2300 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2301 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2302 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2303 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2304 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2305 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2306 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2307 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2308 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2309 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2310 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2311 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2312 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2313 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2314 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2315 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2316 Fuel Pump Switch/Engine Oil Pressure Gage Sensor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 2317 Fuel Pump Relay Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 2318 Oil Pressure Switch (For Fuel Pump): Description and Operation Fuel Pump - Oil Pressure Switch As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Sensors and Switches - Engine > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 2319 Oil Pressure Switch (For Fuel Pump): Service and Repair Fuel Pump - Oil Pressure Switch REMOVE OR DISCONNECT 1. Disconnect electrical connector. 2. Fuel pump switch and oil pressure sensor. INSTALL OR CONNECT 1. Fuel pump switch and oil pressure sensor. 2. Tighten to 12 Nm (106 lb in.) 3. Electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Timing Components > Timing Chain > Component Information > Service and Repair > Interference Engine Timing Chain: Service and Repair Interference Engine The OE manufacture does not specify if this engine is an interference engine or not. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Timing Components > Timing Chain > Component Information > Service and Repair > Interference Engine > Page 2325 Timing Chain: Service and Repair Timing Chain and Sprocket 5.7L Shown 4.3L Similar 1. Remove engine front cover. 2. Remove crankshaft oil slinger. 3. Crank engine until timing marks on sprockets are in alignment, Fig.9. 4. Remove three camshaft to sprocket bolts. 5. Remove camshaft sprocket and timing chain together. Sprocket is a light press fit on camshaft for approximately 1/8 inch. If sprocket does not come off easily, a light blow with a plastic hammer on lower edge of sprocket should dislodge it. 6. If crankshaft sprocket is to be replaced, remove it with a suitable gear puller. Install new sprocket, aligning key and keyway. 7. Install chain on camshaft sprocket. Hold sprocket vertical with chain hanging below and shift around to align timing marks on sprockets. 8. Align dowel in camshaft with dowel hole in sprocket and install sprocket on camshaft. Do not attempt to drive sprocket on camshaft as welch plug at rear of engine can be dislodged. 9. Draw sprocket onto camshaft, using the three mounting bolts. Tighten to specifications. 10. Lubricate timing chain with engine oil and install cover. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Timing Components > Timing Cover > Component Information > Service and Repair Timing Cover: Service and Repair On all engines the cover oil seal may be replaced without taking off the timing gear cover. After removing the vibration damper, pry out the old seal with a screwdriver. Install the new seal with the lip or open end toward inside of cover and drive it into position. 1. Remove water pump. 2. Remove crankshaft balancer and hub. 3. Remove distributor. 4. Remove oil pan and gasket. 5. Remove front cover retaining screws and front cover. 6. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Fuel Pressure > Diagnostic Connector - Fuel Pump > Component Information > Locations Diagnostic Connector - Fuel Pump: Locations The fuel pump test connector is located in the engine compartment near the A/C accumulator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations Fuel Pressure Test Port Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations > Page 2337 Fuel Pressure Test Port: Service and Repair Fuel Test Port Valve CLEAN ^ Area around fuel pressure connection with GM X-3OA or equivalent. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery System / Service and Repair. 3. Fuel pressure connection valve assembly. INSTALL OR CONNECT 1. Fuel pressure connection valve assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ Turn ignition switch to the "ON" position for two seconds, then turn to the "OFF" position for ten seconds. Again turn to "ON" position, and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air/Fuel Mixture > System Information > Specifications Air/Fuel Mixture: Specifications The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air/Fuel Mixture > System Information > Specifications > Page 2341 Air/Fuel Mixture: Adjustments The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Idle Speed > System Information > Specifications Idle Speed: Specifications The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Idle Speed > System Information > Specifications > Page 2345 Idle Speed: Adjustments The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Cleaner Fresh Air Duct/Hose > Component Information > Locations Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: Customer Interest Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 2358 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: All Technical Service Bulletins Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 2364 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 2365 Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 2366 Air Filter Element: Service and Repair Air Ducting Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 2367 REMOVE OR DISCONNECT 1. Loosen wing nuts at front of air cleaner housing. 2. Lift air cleaner lid, Mass Air Flow (MAF) sensor and resonator as a unit. 3. Remove air filter element. INSTALL OR CONNECT 1. Install air filter element. 2. Move air cleaner lid, MAF sensor and resonator into place. 3. Tighten wing nuts. 4. Check clamps at MAF sensor and tighten if necessary. 5. Check joints between duct, resonators and throttle body for possible air leaks. Repair if necessary. NOTICE: If the Mass Air Flow (MAF) sensor is installed backwards, the system will go rich. An arrow cast into the plastic portion of the sensor indicates proper air flow direction. The arrow must point toward the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Fuel Filter > Fuel Pressure Release > System Information > Service and Repair Fuel Pressure Release: Service and Repair WARNING: - To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing fuel system components. - After relieving the fuel system pressure a small amount of fuel may be released when servicing fuel lines or connections. In order to reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting, to catch any fuel that may leak out. Place the shop towel in an approved container when the disconnect is complete. Fuel Pressure Test Port PROCEDURE: 1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine. 2. Loosen the fuel filler cap to relieve tank pressure. 3. Connect the J 34730-1 fuel pressure gauge to the fuel pressure connection on the fuel rail. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage. 4. Install a bleed hose into an approved container and open the valve slowly to relieve system pressure. Fuel connections are now safe for servicing. 5. Drain any fuel remaining in the gauge into an approved container. NOTE: After repairs are complete, tighten the fuel cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Firing Order > Component Information > Specifications > Ignition Firing Order Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Ignition Timing > Number One Cylinder > Component Information > Locations > Number 1 Cylinder Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation Timing Marks and Indicators: Locations Crankshaft Rotation Crankshaft Rotation (Typical Crankshaft Pulley) Crankshaft rotation is clockwise when viewed from in front of the crankshaft pulley as shown in the generic image. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation > Page 2385 Timing Marks and Indicators: Locations Timing Marks The ignition timing is completely controlled by the Powertrain Control Module (PCM). No timing reference marks are provided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications Spark Plug Wire: Specifications Wire Harness Support Bolt / Screw ............................................................................................................................................................ 40 Nm (30 lb ft.) Wire Harness Support Channel Bolt / Screw (Right) ................................................................................................................................ 12 Nm (106 lb in.) Wire Harness Support Channel Bolt/Screw (Left) ..................................................................................................................................... 12 Nm (106 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2389 Spark Plug Wire: Locations Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2390 Spark Plug Harness Routing The spark plug wires run down both sides of the engine block under the exhaust manifolds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2391 Spark Plug Wire: Description and Operation The spark plug wire hamess assemblies use carbon impregnated cord conductors, encased in 8 mm (5 / 16-inch) diameter silicone jackets. The silicone jackets withstand very high temperatures and also provide excellent insulation for the high voltage of the system. Silicone spark plug boots form a tight seal to the spark plugs. The material used to construct spark plug wires is very soft. This wire will withstand more heat and carry a higher voltage, but chaffing and cutting become easier. The spark plug wires must be routed correctly to prevent chafing or cutting. When removing a spark plug wire from a spark plug, twist the boot on the spark plug one-half turn while pulling on the boot. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2392 Spark Plug Wire: Testing and Inspection Inspect spark plug wires visually first for any cuts, burns, or damage. While engine is running, inspect for any arcing to ground or other components. Use a spray bottle to lightly coat the spark plug wires with water while observing idle quality. If idle quality diminishes or engine stalls, spark plug wires should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2393 Spark Plug Wire: Service and Repair Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2394 Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2395 Spark Plug Harness Routing NOTICE: The boots should be twisted one-half turn while removing. Do not pull on the wire harnesses to remove them from the spark plugs. Pull on the boots, or use a tool designed for this purpose. REMOVE OR DISCONNECT Numbers included in this procedure refer to caption numbers in the included images. 1. Left bank spark plug wire boots from spark plugs. 2. Left bank spark plug wire harness support channel bolts / screws (19) and channel. Rear bolt / screw (19) is located behind exhaust manifold takedown. Loosen this bolt / screw using a 10 mm wrench then slide channel upward to disengage from bolt / screw (19). 3. Left bank spark plug wire harness from clip (17) located behind air injection reactor (AIR) pump. 4. Right bank spark plug wire boots from spark plugs. 5. Air intake resonator. With mechanical cooling fan: A. Upper radiator fan shroud, B. Loosen fan pulley nuts. C. Fan belt. D. Mechanical fan and pulley. E. Mechanical fan pulley bracket nuts and bracket. F. Radiator outlet pipe nuts from A/C compressor mounting studs. 6. Serpentine drive belt. 7. Raise and suitably support vehicle. 8. Transmission oil cooler line support bolt / screw from accessory drive bracket. 9. Serpentine drive belt tensioner bolts/screws and tensioner. 10. A/C compressor attaching bolts/screws Reposition A/C compressor to provide access to front wire harness support (27). 11. Right wire harness support bolt / screw (28). 12. Right wire harness from support (27). 13. Left and right bank spark plug wire harnesses (6) from distributor. 14. Left wire harness from clips (17, 20, 21 and 23). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 2396 ^ Insert screwdriver into tab on top of clip to disengage. 15. Right wire harness from clips (16, 17, and 21). ^ Insert screwdriver into tab on top of clip to disengage. NOTICE: When replacing spark plug wire harnesses (secondary wiring), route the wire harnesses correctly and through the proper retainers. Failure to route the wire harnesses properly can lead to radio ignition noise and cross-firing of the spark plugs, or shorting of the leads to ground. INSTALL OR CONNECT 1. Right wire harness to clips (16, 17 and 21). 2. Left wire harness to clips (17, 20, 21 and 23). 3. Right wire harness to support (27). 4. Right wire harness support bolt / screw (28). Tighten ^ Bolt / screw (28) to 40 Nm (30 lb ft.). 5. A/C compressor to bracket. 6. A/C compressor attaching bolts / screws and rear bracket nut. Tighten A. A/C compressor bolts / screws to 50 Nm (37 lb ft.). B. A/C compressor rear bracket nut to 41 Nm (30 lb ft.). 7. Serpentine drive belt tensioner and tensioner bolts / screws. Tighten ^ Tensioner bolts / screws to 25 Nm (18 lb ft.). 8. Transmission oil cooler line support bolt / screw. Tighten ^ Oil cooler line support bolt / screw to 1.9 Nm (17 lb in.). 9. Lower vehicle. 10. Serpentine drive belt. With mechanical cooling fan: A. Radiator outlet pipe nuts from A/C compressor mounting studs. Tighten ^ Radiator outlet pipe nuts to 16 Nm (12 lb ft.). B. Mechanical fan pulley bracket nuts and bracket. Tighten ^ Mechanical fan pulley bracket nuts to 50 Nm (37 lb .ft). C. Mechanical fan pulley, fan and nuts. ^ Finger tighten only. D. Fan belt. Tighten ^ Mechanical fan nuts to 26 Nm (19 lb ft.). E. Upper radiator fan shroud. 11. Air intake resonator. 12. Right bank spark plug wire boots to spark plugs. 13. Left bank spark plug wire harness to clip (17) located behind AIR pump. 14. Left bank spark plug wire harness support channel and bolts/screws (19). Rear bolt / screw (19) is located behind exhaust manifold takedown. Slide channel onto bolt / screw (19) then tighten using a 10 mm wrench. 15. Left bank spark plug wire harness boots to spark plugs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Specifications Distributor Cap: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement Distributor Cap: Service and Repair Replacement Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Distributor cap (30). 2. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 3. Vacuum harness assembly to distributor assembly. 4. Connect four-terminal PCM connector to distributor. 5. Spark plug wire harness assemblies to distributor assembly. 6. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement > Page 2403 Distributor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications Ignition Rotor: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Distributor Rotor Bolt / Screw .............................................................................................................. ....................................................... 0.7 Nm (6 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 2407 Ignition Rotor: Service and Repair Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). 7. Rotor bolts / screws (32) using J 39998 or equivalent. 8. Rotor assembly (32). 9. Distributor cover (33) and shield (34). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Shield (34) and distributor cover (33). 2. Rotor (32). 3. Rotor bolts / screws (31) using J 39998 or equivalent. Tighten ^ Rotor bolts / screws (31) to 0.7 Nm (61 lb in.). 4. Distributor cap (30). 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 2408 ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 6. Vacuum harness assembly to distributor assembly. 7. Connect four-terminal PCM connector to distributor. 8. Spark plug wire harness assemblies to distributor assembly. 9. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications Spark Plug: Specifications Spark Plug Install Torque .................................................................................................................... ........................................................ 27 Nm (20 lb ft.) Spark Plug Gap ................................................................................................................................... ........................................................ 1.27 mm (0.050") Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 2412 Spark Plug Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 2413 Spark Plug: Service Precautions It is important that technicians wash their hands after handling coated spark plugs and before smoking. The coating itself is a nonhazardous material and incidental contact will not cause any adverse affects. However, exposure to polymer vapors (the result of a cigarette being coated from handling, then burned) may cause flu like symptoms and should be avoided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 2414 Spark Plug ID Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 2415 Spark Plug: Description and Operation Platinum-tipped, resistor-type, tapered-seat spark plugs are used on the engine assembly. No gasket is used on these tapered-seat spark plugs. When replacing spark plugs, use only the type specified. Normal service is assumed to be a mixture of idling, slow speed, and high speed driving. Occasional or intermittent high-speed driving is needed for good spark plug performance. It gives increased combustion heat, burning away carbon or oxides that have built up from frequent idling, or continual stop-and-go driving. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 2416 Spark Plug: Testing and Inspection WORN OR DIRTY Worn or dirty spark plugs may give satisfactory operation at idling speed, but frequently fail at higher rpm. Faulty spark plugs may cause poor fuel economy, power loss, loss of speed, hard starting and generally poor engine performance. Follow the scheduled maintenance service recommendations to assure satisfactory spark plug performance. NORMAL Normal spark plug operation will result in brown to grayish - tan deposits appearing on the portion of the spark plug that projects into the cylinder area. A small amount of red - brown, yellow, and white powdery material may also be present on the insulator tip around the center electrode. These deposits are normal combustion by-products of fuels and lubricating oils with additives. MISFIRING Engine assemblies which are not running properly are often referred to as "misfiring." This means the ignition spark is not igniting the fuel/air mixture at the proper time, While other ignition and fuel system causes must also be considered, possible causes include ignition system conditions which allow the spark voltage to reach ground in some other manner than by jumping across the air gap at the tip of the spark plug, leaving the fuel/air mixture unburned. Misfiring may also occur when the tip of the spark plug becomes overheated and ignites the mixture before the spark jumps. This is referred to as "pre-ignition." CARBON FOULING Carbon fouling of the spark plug is indicated by dry, black carbon (soot) deposits on the portion of the spark plug in the cylinder. Excessive idling and slow speeds under light engine loads can keep the spark plug temperatures so low that these deposits are not burned off. Over - rich fuel mixtures or poor ignition system output may also be the cause. OIL FOULING Oil fouling of the spark plug is indicated by wet oily deposits on the portion of the spark plug in the cylinder. This may be caused by oil getting past worn piston rings. This condition also may occur during break-in of new or newly overhauled engine assemblies. DEPOSITS Deposit fouling of the spark plug occurs when the normal red - brown, yellow or white deposits of combustion by - products become sufficient to cause misfiring. In some cases, these deposits may melt and form a shiny glaze on the insulator around the center electrode. If the fouling is found in only one or two cylinders, valve stem clearances or intake valve seals may be allowing excess lubricating oil to enter the cylinder, particularly if the deposits are heavier on the side of the spark plug that was facing the intake valve. CRACKED OR BROKEN Cracked or broken insulators may be the result of improper installation or heat shock to the insulator material. Upper insulators can be broken when a poorly fitting tool is used during installation or removal, or when the park plug is hit from the outside. Cracks in the upper insulator may be inside the shell and not visible. Also, the breakage may not cause problems until oil or moisture penetrates the crack later. A broken or cracked lower insulator tip (around the center electrode) may result from "heat shock" (spark plug suddenly operating too hot). "Heat shock" breakage in the lower insulator tip generally occurs during severe engine operating conditions (high speeds or heavy loading) and may be caused by over - advanced timing or low grade fuels. Heat shock refers to a rapid increase in the tip temperature that causes the insulator material to crack. Damage during gapping can happen if the gapping tool is pushed against the center electrode or the insulator around it, causing the insulator to crack. When gapping a spark plug, make the adjustment by only bending the ground side terminal, keeping the tool clear of other parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 2417 Spark Plug: Service and Repair Spark Plug Assembly REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Spark plug wire harness assemblies from spark plugs. Refer to "Spark Plug Wire Harness Assembly Replacement" in this section. ^ Note positions of wires before removing. NOTICE: Clean dirt and debris from spark plug recess areas. 3. Spark plugs from cylinder head assemblies. NOTICE: Be sure spark plugs thread smoothly into cylinder head assemblies and are fully seated. Cross threading or failing to fully seat spark plugs can cause overheating of spark plugs, exhaust blow-by, or thread damage. Follow recommended torque specifications carefully. Over or under - tightening can also cause severe damage to cylinder head assemblies or spark plug. Check spark plug gap using a wire type gauge before installing. If spark plug gaps are not adjusted correctly, engine idle quality may be seriously affected. A wire type gauge must be used (as opposed to a flat feeler type gauge) to insure an accurate reading. INSTALL OR CONNECT 1. Spark plugs to cylinder head assemblies. Tighten ^ Spark plugs to 27 Nm (20 lb ft.). 2. Spark plug wire harness assemblies, routed properly as note during removal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Compression Check > System Information > Specifications Compression Check: Specifications The lowest reading cylinder should not be less than 70% of the highest and no cylinder reading should be less than 689 kPa (100 psi). Perform compression test with engine at normal operating temperature, spark plugs removed and throttle wide open. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Valve Clearance > System Information > Specifications Valve Clearance: Specifications VALVE LASH Turn rocker arm stud nut until all lash is eliminated (zero lash), then tighten nut additional turn in 1/4 turn increments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Tune-up and Engine Performance Checks > Valve Clearance > System Information > Specifications > Page 2424 Valve Clearance: Adjustments Fig. 5 Valve Lash Adjustment Adjust valves, Fig.5, with engine at normal operating temperature. Rotate engine until No. 1 cylinder is in position to fire. Adjust exhaust valves 1-3-4-8 and intake valves 1-2-5-7. Crank engine one complete revolution, then adjust exhaust valves 2-5-6-7 and intake vales 3-4-6-8. On all engines, the following procedure, performed with the engine running, should only be performed if readjustment is required. 1. After engine has been warmed up to normal operating temperature, remove valve cover and install a new valve cover gasket. 2. With engine running at idle speed, back off valve rocker arm nut until rocker arm starts to clatter. 3. Turn rocker arm nut down slowly until clatter just stops. This is the zero lash position. 4. Turn nut down 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat additional 1/4 turns, pausing 10 seconds each time, until nut has been turned down the number of turns listed in "Valve Clearance Specifications chart from the zero lash position. This preload adjustment must be done slowly to allow lifter to adjust itself to prevent the possibility of interference between valve head and top of piston, which might result in internal damage and/or bent push rods. Noisy lifters should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly Water Pump: Service and Repair Coolant Pump Driveshaft Assembly This Article has been updated with TSB No. 57-61-28 COOLANT PUMP DRIVESHAFT ASSEMBLY Fig. 23 Water Pump & Thermostat Replacement TOOLS REQUIRED: ^ J 39243 Driven Gear Assembly Remover ^ J 41546 Driven Gear Assembly Installer ^ J 39089 Coolant Pump Shaft 0-Ring Protector Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2429 REMOVE OR DISCONNECT 1. Engine front cover assembly. 2. Rotate crankshaft assembly until timing marks punched on crankshaft sprocket and camshaft sprocket are aligned. 3. Camshaft sprocket bolts/screws. 4. Camshaft sprocket and timing chain assembly. NOTICE: Do not turn the crankshaft assembly after the timing chain has been removed to prevent damage to piston assemblies or valves. 5. Coolant pump bearing retainer bolts/screws and coolant pump driveshaft assembly using J 39243. ^ Remove and discard 0-ring from coolant pump drive-shaft assembly. INSTALL OR CONNECT 1. Coolant pump drive shaft assembly using J 39092. 2. Coolant pump bearing retainer bolts/screws. TIGHTEN ^ Coolant pump bearing retainer bolts/screws to 12 Nm (108 lb. in.). 3. Camshaft sprocket and timing chain assembly. ^ Camshaft sprocket and coolant pump driveshaft gears must mesh, or damage to camshaft retainer could occur. 4. Camshaft sprocket bolts/screws. ^ Make sure that camshaft and crankshaft timing marks align. TIGHTEN ^ Camshaft sprocket bolts/screws to 28 Nm (21 lb. ft.). 5. New 0-ring to coolant pump driveshaft assembly using J 39089. 6. Engine front cover assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2430 Water Pump: Service and Repair Water/Coolant Pump WATER PUMP REPLACEMENT Fig. 17 Water Pump Replacement REMOVAL PROCEDURE The camshaft sprocket gear drives the water pump by using a drive shaft and coupling. Keep the ignition wires connected to the distributor until the water pump is removed and all the coolant has been drained. 1. Drain the engine coolant. 2. Remove the air cleaner resonator bracket nuts, if equipped with a mechanical fan. 3. If the vehicle is equipped with a mechanical fan, remove the air cleaner resonator by loosening the clamp and sliding the resonator off the studs. 4. If the vehicle is equipped with a mechanical fan, remove the air intake duct. 5. If the vehicle is equipped with a mechanical fan, remove the radiator fan upper shroud. 6. If the vehicle is equipped with a mechanical fan, remove the fan belt from the tensioner. 7. If the vehicle is equipped with a mechanical fan, remove the fan blade clutch nuts and the fan blade with the clutch attached. 8. Remove the engine coolant and the heater hoses from the water pump. 9. If the vehicle is equipped with a mechanical fan, remove the fan pulley. 10. If the vehicle is equipped with a mechanical fan, remove the coolant fan pulley bracket nuts. 11. If the vehicle is equipped with a mechanical fan, remove the coolant fan pulley bracket. 12. Remove the electrical connector from the coolant sensor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2431 13. Remove the secondary air injection pump and bracket. 14. Remove the water pump bolts and the stud. 15. Remove the water pump and gaskets. 16. Remove the water pump driveshaft coupling and the seals. ^ Discard the seals. CLEAN ^ The water pump gasket surfaces. ^ The water pump bolts. ^ The coolant fan pulley bracket studs, if removed. INSTALLATION PROCEDURE 1. Install the water pump driveshaft coupling and the new seals. 2. Install the water pump and the gaskets. 3. Install the water pump bolts and the stud. TIGHTEN ^ Bolts and the stud to 41 Nm (30 lb ft). NOTICE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. 4. Install the secondary air injection pump and bracket. Refer to Refer to Air Pump in Engine Controls. 5. Install the electrical connector to the coolant sensor. 6. Install the coolant fan pulley bracket, if removed. 7. Install the coolant fan pulley bracket nuts, if removed. TIGHTEN ^ Nuts to 50 Nm (37 lb ft). 8. Install the fan pulley, if removed. 9. Install the fan blade with the clutch attached and the nuts, if removed. TIGHTEN ^ Nuts to 26 Nm (19 lb ft). 10. Install the engine coolant hoses and the heater hoses to the water pump. 11. Install the fan belt to the tensioner if the fan belt has been removed. 12. Install the radiator fan upper shroud if the radiator fan upper shroud has been removed. 13. Install the air intake duct, if removed. 14. If the air cleaner resonator has been removed, install the air cleaner resonator by sliding the resonator over the studs and tightening the clamp until snug. 15. Install the air cleaner resonator bracket nuts, if removed. TIGHTEN ^ Nuts to 10 Nm (89 lb in). 16. Refill and bleed the cooling system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Engine > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2432 Water Pump: Service and Repair Water Pump Disassembly The OEM service manual does not provide water pump assembly service and repair information. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information Coolant: Technical Service Bulletins Cooling System - Coolant Recycling Information Bulletin No.: 00-06-02-006D Date: August 15, 2006 INFORMATION Subject: Engine Coolant Recycling and Warranty Information Models: 2007 and Prior GM Passenger Cars and Trucks (Including Saturn) 2007 and Prior HUMMER Vehicles 2005-2007 Saab 9-7X Attention: Please address this bulletin to the Warranty Claims Administrator and the Service Manager. Supercede: This bulletin is being revised to adjust the title and Include Warranty Information. Please discard Corporate Bulletin Number 00-06-02-006C (Section 06 - Engine/Propulsion System). Coolant Reimbursement Policy General Motors supports the use of recycled engine coolant for warranty repairs/service, providing a GM approved engine coolant recycling system is used. Recycled coolant will be reimbursed at the GMSPO dealer price for new coolant plus the appropriate mark-up. When coolant replacement is required during a warranty repair, it is crucial that only the relative amount of engine coolant concentrate be charged, not the total diluted volume. In other words: if you are using two gallons of pre-diluted (50:50) recycled engine coolant to service a vehicle, you may request reimbursement for one gallon of GM Goodwrench engine coolant concentrate at the dealer price plus the appropriate warranty parts handling allowance. Licensed Approved DEX-COOL(R) Providers Important: USE OF NON-APPROVED VIRGIN OR RECYCLED DEX-COOL(R) OR DEVIATIONS IN THE FORM OF ALTERNATE CHEMICALS OR ALTERATION OF EQUIPMENT, WILL VOID THE GM ENDORSEMENT, MAY DEGRADE COOLANT SYSTEM INTEGRITY AND PLACE THE COOLING SYSTEM WARRANTY UNDER JEOPARDY. Shown in Table 1 are the only current licensed and approved providers of DEX-COOL(R). Products that are advertised as "COMPATIBLE" or "RECOMMENDED" for use with DEX-COOL(R) have not been tested or approved by General Motors. Non-approved coolants may degrade the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 2438 coolant system integrity and will no longer be considered a 5 yr/150,000 mile (240,000 km) coolant. Coolant Removal Services/Recycling The tables include all coolant recycling processes currently approved by GM. Also included is a primary phone number and demographic information. Used DEX-COOL(R) can be combined with used conventional coolant (green) for recycling. Depending on the recycling service and/or equipment, it is then designated as a conventional 2 yr/30,000 mile (50,000 km) coolant or DEX-COOL(R) 5 yr/150,000 mile (240,000 km) coolant. Recycled coolants as designated in this bulletin may be used during the vehicle(s) warranty period. DEX-COOL(R) Recycling The DEX-COOL(R) recycling service listed in Table 2 has been approved for recycling waste engine coolants (DEX-COOL) or conventional) to DEX-COOL(R) with 5 yr/150,000 mile (240,000 km) usability. Recycling Fluid Technologies is the only licensed provider of Recycled DEX-COOL(R) meeting GM6277M specifications and utilizes GM approved inhibitor packages. This is currently a limited program being monitored by GM Service Operations which will be expanded as demand increases. Conventional (Green) Recycling Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 2439 Processes shown in the Table 3 are capable of recycling waste engine coolants (DEX-COOL(R) or conventional) to a conventional (green) coolant. Recycling conventional coolant can be accomplished at your facility by a technician using approved EQUIPMENT (listed by model number in Table 3), or by an approved coolant recycling SERVICE which may recycle the coolant at your facility or at an offsite operation. Refer to the table for GM approved coolant recyclers in either of these two categories. Should you decide to recycle the coolant yourself, strict adherence to the operating procedures is imperative. Use ONLY the inhibitor chemicals supplied by the respective (GM approved) recycling equipment manufacturer. Sealing Tablets Cooling System Sealing Tablets (Seal Tabs) should not be used as a regular maintenance item after servicing an engine cooling system. Discoloration of coolant can occur if too many seal tabs have been inserted into the cooling system. This can occur if seal tabs are repeatedly used over the service life of a vehicle. Where appropriate, seal tabs may be used if diagnostics fail to repair a small leak in the cooling system. When a condition appears in which seal tabs may be recommended, a specific bulletin will be released describing their proper usage. Water Quality The integrity of the coolant is dependent upon the quality of DEX-COOL(R) and water. DEX-COOL(R) is a product that has enhanced protection capability as well as an extended service interval. These enhanced properties may be jeopardized by combining DEX-COOL(R) with poor quality water. If you suspect the water in your area of being poor quality, it is recommended you use distilled or de-ionized water with DEX-COOL(R). "Pink" DEX-COOL(R) DEX-COOL(R) is orange in color to distinguish it from other coolants. Due to inconsistencies in the mixing of the dyes used with DEX-COOL(R), some batches may appear pink after time. The color shift from orange to pink does not affect the integrity of the coolant, and still maintains the 5 yr/150,000 mile (240,000 km) service interval. Back Service Only use DEX-COOL(R) if the vehicle was originally equipped with DEX-COOL(R). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 2440 Contamination Mixing conventional green coolant with DEX-COOL(R) will degrade the service interval from 5 yrs./150,000 miles (240,000 km) to 2 yrs./30,000 miles (50,000 km) if left in the contaminated condition. If contamination occurs, the cooling system must be flushed twice immediately and re-filled with a 50/50 mixture of DEX-COOL(R) and clean water in order to preserve the enhanced properties and extended service interval of DEX-COOL(R). After 5 years/150,000 miles (240,000 km) After 5 yrs/150,000 miles (240,000 km), the coolant should be changed, preferably using a coolant exchanger. If the vehicle was originally equipped with DEX-COOL(R) and has not had problems with contamination from non-DEX-COOL(R) coolants, then the service interval remains the same, and the coolant does not need to be changed for another 5 yrs/150,000 miles (240,000 km) Equipment (Coolant Exchangers) The preferred method of performing coolant replacement is to use a coolant exchanger. A coolant exchanger can replace virtually all of the old coolant with new coolant. Coolant exchangers can be used to perform coolant replacement without spillage, and facilitate easy waste collection. They can also be used to lower the coolant level in a vehicle to allow for less messy servicing of cooling system components. It is recommended that you use a coolant exchanger with a vacuum feature facilitates removing trapped air from the cooling system. This is a substantial time savings over repeatedly thermo cycling the vehicle and topping-off the radiator. The vacuum feature also allows venting of a hot system to relieve system pressure. Approved coolant exchangers are available through the GMDE (General Motors Dealer Equipment) program. For refilling a cooling system that has been partially or fully drained for repairs other than coolant replacement, the Vac-N-Fill Coolant Refill Tool (GE-47716) is recommended to facilitate removal of trapped air from the cooling system during refill. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 2441 Coolant: Technical Service Bulletins Engine Coolant - Information on Back Service File In Section: 6 - Engine Bulletin No: 53-62-02 Date: November, 1995 Subject: DEX-COOL(TM) Engine Coolant - Information on Back service Models: 1994-95 Passenger Cars and Trucks A new extended-life engine coolant called DEX-COOL(TM) is currently being used in all General Motors' vehicles (excluding Chevrolet Geo and Saturn). Refer to bulletin 53-62-01 for general service information. Backservice DEX-COOL(TM) may be used in General Motors vehicles originally built with conventional (green) coolant with the following considerations: ^ Vehicles eligible for back service are 1994 and 1995 models (excluding 1994 J Body with 4 cylinder engines). ^ The service interval for DEX-COOL(TM) introduced into an older model vehicle originally built with "green" coolant will be 2 years/30,000 miles (50,000 Km) (not 5 years/100,000 miles (160,000 Km)). ^ All the "green" coolant must be removed from the cooling system by means of a system flush. This may be accomplished with a water flushing device or a GMDE waterless coolant changer (use a unit dedicated to "green" coolant, not DEX-COOL TM). Important: When using a GMDE waterless coolant changer, conduct the procedure twice, once with water, and once with DEX-COOL(TM) Backservice with DEX-COOL(TM) is advocated because of enhanced water pump seal durability experienced with this coolant. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant > Component Information > Technical Service Bulletins > Cooling System - Coolant Recycling Information > Page 2442 Coolant: Technical Service Bulletins Extended Life Engine Coolant - DEX-COOL(TM) FILE IN SECTION: 6 - Engine BULLETIN NO.: 53-62-01 DATE: June, 1995 SUBJECT: New Extended Life Engine Coolant Known as DEX-COOL(TM) MODELS: 1995 Passenger Cars and Trucks A new extended life engine coolant known as "DEX-COOL(TM)" will be used in all General Motors vehicles. Some trucks will be filled with DEX-COOL TM beginning in late May; most vehicles will convert in July, 1995 with the remaining vehicles to convert by January, 1996. Most of these vehicles will be 1995 models. All production for 1996 models will utilize DEX-COOL(TM). It is imperative to note the following about DEX-COOL(TM) engine coolant: ^ IT IS ORANGE IN COLOR TO DISTINGUISH IT FROM CONVENTIONAL COOLANT. ^ THE SERVICE CHANGE INTERVAL ON VEHICLES WHICH ARE BUILT WITH DEX-COOL(TM) IS 5 YEARS/100,000 MILES, WHICHEVER OCCURS FIRST. ^ TO MAINTAIN FULL CORROSION PROTECTION DURABILITY, DEX-COOL (TM) MUST NOT BE MIXED WITH CONVENTIONAL (CONTAINING SILICATE) ENGINE COOLANTS. ^ DEX-COOL(TM) IS AN ETHYLENE GYLCOL BASED PRODUCT, THEREFORE, BOIL AND FREEZE PROTECTION ARE MEASURED IN THE SAME FASHION AS CONVENTIONAL COOLANTS. TO FULLY REALIZE ITS MANY ADVANTAGES, DEX-COOL(TM) MUST NEVER BE MIXED WITH CONVENTIONAL COOLANTS. It is particularly important to top-off new vehicles with DEX-COOL(TM) DEX-COOL(TM) forms a protective film on aluminum surfaces, however, if a vehicle with less than 3,000 miles is topped-off with conventional coolant, aluminum corrosion may occur. DEX-COOL(TM) CAN BECOME CONTAMINATED BY INADVERTENTLY TOPPING-OFF WITH CONVENTIONAL COOLANT, ADDING CONVENTIONAL COOLANT TO THE RADIATOR, OR EVEN IF FILL/DRAIN CONTAINERS ARE SHARED BETWEEN COOLANTS. If contamination occurs on a new vehicle (i.e. during vehicle prep), the cooling system must be immediately drained and refilled with DEX-COOL(TM) If contamination with conventional coolant occurs after the vehicle has been driven for at least 3,000 miles, no short-term problems will occur; however, the service change interval will be reduced from 5 years/100,000 miles to 2 years/30,000 miles. More information on DEX-COOL(TM) engine coolant service procedures can be found in the 1996 Service Manuals and a video tape which will be issued by STG. Vehicles which contain DEX-COOL(TM) can be identified by a special underhood label which states "USE DEX-COOL(TM) COOLANT ONLY. .. meeting Spec. 6277M". They may also be identified by the coolant's orange color and the information contained in the Owner's Manual. REGARDING COOLANT RECYCLING Engine coolant recycling is affected by DEX-COOL(TM) as follows. Used DEX-COOL(TM) can be mixed into your "used" conventional coolant storage vessel and the mixture recycled in the same manner as you are accustomed to. This recycled mixture of conventional and DEX-COOL(TM) coolant must be used as a 2 year/30,000 mile conventional coolant and should not be used in vehicles originally equipped with DEX-COOL(TM) When servicing vehicles originally equipped with DEX-COOL(TM), use only Goodwrench-DEX-COOL(TM) Additional research will be conducted to evaluate the feasibility of recycling DEX-COOL(TM) to DEX-COOL(TM) in the near future. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant > Component Information > Technical Service Bulletins > Page 2443 Coolant: Specifications Mixture .......................................................................................................................................................... 50/50 of water and ethylene glycol antifreeze Capacity Without Heavy-Duty Radiator .............................................................................................................................................................. 13.5 liters (14.3 qt) With Heavy-Duty Radiator .................................................................................... ............................................................................... 13.8 liters (14.6 qt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant Level Indicator Lamp > Component Information > Description and Operation Coolant Level Indicator Lamp: Description and Operation DESCRIPTION This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. OPERATION Some vehicles use a buzzer or indicator lamp to convey a low coolant level condition. The buzzer or lamp is activated by a sensor, located in the radiator, when the coolant level becomes one quart low, or more. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator Off W/Coolant Level Low Fig. 97 Chart 6: Low Coolant Level Indicator Inoperative W/Coolant Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low > Page 2449 Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator On w/Coolant Level OK Fig. 96 Chart 5: Low Coolant Level Indicator On W/Coolant Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Page 2450 Coolant Level Indicator Lamp: Service and Repair This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant Level Sensor > Component Information > Locations Rear Side Radiator Support, Coolant Fans Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Coolant Reservoir > Component Information > Locations Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Locations > Secondary Engine Electric Cooling Fan Connector Rear Side Radiator Support, Coolant Fans Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Locations > Secondary Engine Electric Cooling Fan Connector > Page 2462 Rear Side Radiator Support, Coolant Fans Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions Radiator Cooling Fan Motor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2465 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2466 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2467 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2468 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2469 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2470 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2471 Radiator Cooling Fan Motor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2472 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2473 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2474 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2475 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2476 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2477 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2478 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2479 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2480 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2481 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2482 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2483 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2484 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2485 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2486 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2487 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2488 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2489 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2490 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2491 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2492 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2493 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2494 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2495 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2496 Radiator Cooling Fan Motor: Electrical Diagrams Base And V03 Extra Capacity Cooling Only Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2497 V08 Heavy Duty Cooling Only Wiring Diagrams Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Diagrams > Diagram Information and Instructions > Page 2498 Cooling Fans, A/C And I/P Indicators This diagram is one part of the Complete set of Powertrain Wiring Diagrams located under Powertrain Management. Refer to this area if you need the accompanying diagram. See: Powertrain Management/Diagrams/Electrical Diagrams Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Description and Operation > Cooling Fan (Heavy Duty) Radiator Cooling Fan Motor: Description and Operation Cooling Fan (Heavy Duty) The primary engine cooling fan in this system is mechanical. The secondary cooling fan is an electric fan. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor > Component Information > Description and Operation > Cooling Fan (Heavy Duty) > Page 2501 Radiator Cooling Fan Motor: Description and Operation Cooling Fans This two fan system is PCM controlled by inputs received from the engine coolant temperature sensor, vehicle speed sensor, and the A/C system. The PCM commands the primary cooling fan On when engine coolant temperature exceeds 225° F, A/C head pressure is above 225 psi and when certain diagnostic trouble codes are set. The primary fan is commanded Off when engine coolant temperature drops below 217° F, or A/C head pressure drops below 180 psi. The secondary cooling fan is commanded On when the engine coolant temperature exceeds 232° F, A/C head pressure is above 248 psi or certain diagnostic trouble codes are set. The PCM commands the secondary fan Off when engine coolant temperature drops below 224° F, or A/C head pressure drops below 203 psi. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor Relay > Component Information > Locations Radiator Cooling Fan Motor Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Motor Relay > Component Information > Locations > Page 2505 Engine Cooling Fan Relay Primary, Secondary Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Radiator Cooling Fan Temperature Sensor / Switch > Component Information > Locations Radiator Cooling Fan Temperature Sensor / Switch: Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Fan Clutch > Component Information > Description and Operation Fan Clutch: Description and Operation Fig. 1 Typical Variable Speed Cooling Fan Fig. 2 Variable Speed Fan W/Flat Bi-Metal Thermostatic Spring Fig. 3 Variable-Speed Fan W/Coiled Bi-Metal Thermostatic Spring The fan drive clutch, Fig. 1 , is a fluid coupling containing silicone oil. Fan speed is regulated by the torque carrying capacity of the silicone oil. The more silicone oil in the coupling, the greater the fan speed; the less silicone oil, the slower the fan speed. Two types of fan drive clutches are in use. On one, Fig.2 , a bi-metallic strip and control piston on the front of the fluid coupling regulates the amount of silicone oil entering the coupling. The bi-metallic strip flexes outward with an increase in surrounding temperature and allows a piston to move outward. The piston opens a valve regulating the flow of silicone oil into the coupling from a reserve chamber. The silicone oil is returned to the reserve chamber through a bleed hole when the valve is closed. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Fan Clutch > Component Information > Description and Operation > Page 2512 On the other type of fan drive clutch, Fig. 3 , a heat-sensitive, bi-metal spring connected to an opening plate brings about a similar result. Both units cause the fan speed to increase with a rise in temperature and to decrease as the temperature goes down. In some cases a Flex-Fan is used instead of a Fan Drive Clutch. Flexible blades vary the volume of air being drawn through the radiator, automatically increasing the pitch at low engine speeds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Fan Clutch > Component Information > Description and Operation > Page 2513 Fan Clutch: Testing and Inspection Fig. 4 Bi-Metal Spring Disengagement Do not operate the engine until the fan has been checked for possible cracks and separations. Run the engine at a fast idle speed (1000 RPM) until normal operating temperature is reached. This process can be expedited by blocking off the front of the radiator with a suitable piece of cardboard. Regardless of temperature, the unit must be operated for at least five minutes before being tested. Stop the engine and, using a glove or a cloth, immediately check the effort required to turn the fan. If considerable effort is required, it can be assumed that the coupling is operating satisfactorily. If very little effort is required to turn the fan, it is an indication that the coupling is not operating properly and should be replaced. If the clutch fan is the coiled bi-metal spring type, it may be tested while the vehicle is being driven. To check, disconnect the bi-metal spring, Fig. 4 , and rotate the spring 90° counterclockwise. This disables the temperature controlled free wheeling feature and the clutch performs like a conventional fan. If this cures the overheating condition, replace the fan clutch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator Cooling Fan > Fan Clutch > Component Information > Description and Operation > Page 2514 Fan Clutch: Service and Repair Fig. 1 Typical Variable Speed Cooling Fan To prevent silicone fluid from draining into fan drive bearing, do not store or place drive unit on bench with rear of shaft pointing downward. The removal procedure for either type of fan clutch assembly is similar for all vehicles. The unit must be unfastened from the water pump, then it may be lifted from the vehicle. The type of unit shown in Fig. 2 may be partially disassembled for inspection and cleaning as follows: 1. Remove capscrews holding assembly together and separate fan from drive clutch. 2. Remove metal strip on front of fan clutch by pushing one end toward fan clutch body to clear retaining bracket. 3. Push strip aside until its opposite end springs out of place, then remove small control piston. 4. Inspect piston for free movement in coupling device. If piston sticks, clean it with emery cloth. If bi-metal strip is damaged, replace entire unit. These strips are not interchangeable. 5. When reassembling, install control piston so that projection on end will contact metal strip, then install metal strip. 6. After reassembly, clean clutch drive with a solvent soaked cloth. Avoid dipping clutch assembly in any type of liquid. 7. Install assembly in vehicle. The coil spring type of fan clutch cannot be disassembled, serviced or repaired. If it does not function properly, it must be replaced with a new unit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications Coolant Temperature Sensor/Switch (For Computer): Specifications Engine Coolant Temperature (ECT) Sensor ................................................................................................................................................ 23 Nm (17 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2519 Coolant Temperature Sensor/Switch (For Computer): Locations Left Front Of Engine The engine coolant temperature sensor is located near water pump. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2520 Coolant Temperature Sensor/Switch (For Computer): Description and Operation Engine Coolant Temperature Sensor The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) immersed in the engine coolant stream. Low coolant temperature produces a high resistance while high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the ECT through a resistor in the PCM and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage. the PCM knows the engine coolant temperature. Engine coolant temperature affects most systems the PCM controls. A failure in the ECT circuit should set either a Diagnostic Trouble Code (DTC) 14 or 15. Remember these DTCs indicate a failure in the engine coolant temperature sensor circuit, so proper use of the chart will lead to either repairing a wiring problem or replacing the sensor to properly repair a problem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2521 Coolant Temperature Sensor/Switch (For Computer): Service and Repair Engine Coolant Temperature Sensor IMPORTANT: Care must be taken when handling engine coolant (ECT) temperature sensor. Damage to engine coolant sensor will affect proper operation of the fuel injection system. REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Relieve coolant pressure. 3. Electrical connector. 4. Carefully back out sensor. INSTALL OR CONNECT 1. Coat threads with sealer. 2. Install sensor in engine. 3. Torque to 23 Nm (17 ft lb). 4. Connect electrical connector. 5. Refill lost coolant. 6. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Engine - Coolant Temperature Sensor/Switch > Radiator Cooling Fan Temperature Sensor / Switch > Component Information > Locations Radiator Cooling Fan Temperature Sensor / Switch: Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Engine - Coolant Temperature Sensor/Switch > Temperature Sensor (Gauge) > Component Information > Locations Temperature Sensor (Gauge): Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Heater Core > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators Heater Core: Technical Service Bulletins Cooling System, A/C - Aluminum Heater Cores/Radiators INFORMATION Bulletin No.: 05-06-02-001A Date: July 16, 2008 Subject: Information On Aluminum Heater Core and/or Radiator Replacement Models: 2005 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2003-2005 HUMMER H2 Supercede: This bulletin is being revised to update the Warranty Information. Please discard Corporate Bulletin Number 05-06-02-001 (Section 06 - Engine/Propulsion System). Important: 2004-05 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX-COOL(R). Refer to the flushing procedure explained later in this bulletin. The following information should be utilized when servicing aluminum heater core and/or radiators on repeat visits. A replacement may be necessary because erosion, corrosion, or insufficient inhibitor levels may cause damage to the heater core, radiator or water pump. A coolant check should be performed whenever a heater core, radiator, or water pump is replaced. The following procedures/ inspections should be done to verify proper coolant effectiveness. Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if the radiator cap or surge tank cap is removed while the engine and radiator are still hot. Important: If the vehicle's coolant is low, drained out, or the customer has repeatedly added coolant or water to the system, then the system should be completely flushed using the procedure explained later in this bulletin. Technician Diagnosis ^ Verify coolant concentration. A 50% coolant/water solution ensures proper freeze and corrosion protection. Inhibitor levels cannot be easily measured in the field, but can be indirectly done by the measurement of coolant concentration. This must be done by using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale), or equivalent, coolant tester. The Refractometer uses a minimal amount of coolant that can be taken from the coolant recovery reservoir, radiator or the engine block. Inexpensive gravity float testers (floating balls) will not completely analyze the coolant concentration fully and should not be used. The concentration levels should be between 50% and 65% coolant concentrate. This mixture will have a freeze point protection of -34 degrees Fahrenheit (-37 degrees Celsius). If the concentration is below 50%, the cooling system must be flushed. ^ Inspect the coolant flow restrictor if the vehicle is equipped with one. Refer to Service Information (SI) and/or the appropriate Service Manual for component location and condition for operation. ^ Verify that no electrolysis is present in the cooling system. This electrolysis test can be performed before or after the system has been repaired. Use a digital voltmeter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. Any voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is often an intermittent condition that occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused from a poorly grounded cooling fan or some other accessory and can be verified by watching the volt meter and turning on and off various accessories or engage the starter motor. Before using one of the following flush procedures, the coolant recovery reservoir must be removed, drained, cleaned and reinstalled before refilling the system. Notice: ^ Using coolant other than DEX‐COOL(R) may cause premature engine, heater core or radiator corrosion. In addition, the engine coolant may require changing sooner, at 30,000 miles (50,000 km) or 24 months, whichever occurs first. Any repairs would not be covered by your warranty. Always use DEX‐COOL(R) (silicate free) coolant in your vehicle. ^ If you use an improper coolant mixture, your engine could overheat and be badly damaged. The repair cost would not be covered by your warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core and other parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Heater Core > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators > Page 2532 Flushing Procedures using DEX-COOL(R) Important: The following procedure recommends refilling the system with DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. This coolant is orange in color and has a service interval of 5 years or 240,000 km (150,000 mi). However, when used on vehicles built prior to the introduction of DEX-COOL(R), maintenance intervals will remain the same as specified in the Owner's Manual. ^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions. ^ If approved cooling system flush and fill machine is not available, drain the coolant and dispose of properly following the draining procedures in the appropriate Service Manual. Refill the system using clear, drinkable water and run the vehicle until the thermostat opens. Repeat and run the vehicle three (3) times to totally remove the old coolant or until the drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with DEX‐COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M, following the refill procedures in the appropriate Service Manual. If a Service Manual is not available, fill half the capacity of the system with 100% DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. Then slowly add clear, drinkable water (preferably distilled) to the system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and reverify the coolant level. If necessary, add clean water to restore the coolant to the appropriate level. Once the system is refilled, reverify the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. The concentration levels should be between 50% and 65%. Flushing Procedures using Conventional Silicated (Green Colored) Coolant Important: 2004-2005 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX‐COOL(R). The Aveo and Wave are filled with conventional, silicated engine coolant that is blue in color. Silicated coolants are typically green in color and are required to be drained, flushed and refilled every 30,000 miles (48,000 km). The Aveo and Wave are to be serviced with conventional, silicated coolant. Use P/N 12378560 (1 gal) (in Canada, use P/N 88862159 (1 L). Refer to the Owner's Manual or Service Information (SI) for further information on OEM coolant. Important: Do not mix the OEM orange colored DEX-COOL(R) coolant with green colored coolant when adding coolant to the system or when servicing the vehicle's cooling system. Mixing the orange and green colored coolants will produce a brown coolant which may be a customer dissatisfier and will not extend the service interval to that of DEX-COOL(R). Conventional silicated coolants offered by GM Service and Parts Operations are green in color. ^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions. ^ If approved cooling systems flush and fill machine is not available, drain coolant and dispose of properly following the draining procedures in appropriate Service Manual. Refill the system using clear, drinkable water and run vehicle until thermostat opens. Repeat and run vehicle three (3) times to totally remove old coolant or until drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with a good quality ethylene glycol base engine coolant, P/N 12378560, 1 gal (in Canada, use P/N 88862159 1 L), conforming to GM specification 1825M, or recycled coolant conforming to GM specification 1825M, following the refill procedures in the appropriate Service Manual. If a Service Manual is not available, fill half the capacity of the system with 100% good quality ethylene glycol base (green colored) engine coolant, P/N 12378560 1 gal., (in Canada, use P/N 88862159 1 L) conforming to GM specification 1825M. Then slowly add clear, drinkable water (preferably distilled) to system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and recheck coolant level. If necessary, add clean water to restore coolant to the appropriate level. Once the system is refilled, recheck the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. Concentration levels should be between 50% and 65%. Parts Information Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Heater Core > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators > Page 2533 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Heater Core > Component Information > Service and Repair > With Air Conditioning Heater Core: Service and Repair With Air Conditioning Fig. 21 Heater Core & Evaporator Core 1. Disconnect battery ground cable, then drain cooling system. 2. Remove heater outlet attaching screw. 3. Disconnect heater core pipe fittings, then disengage pipe from fitting. 4. Remove righthand instrument insulator panel attaching screws, then pull panel rearward to disconnect. 5. Remove instrument panel lower reinforcement attaching nut and screw. 6. Disconnect lower evaporator case vacuum electrical connectors. 7. Remove righthand pillar trim finish panel, then roll carpet back to gain access. 8. Remove seven lower evaporator case attaching screws, then remove lower evaporator case. 9. Remove heater core attaching straps and screws, then pull heater core rearward working heater tubes out of seal, Fig. 21. 10. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Heater Core > Component Information > Service and Repair > With Air Conditioning > Page 2536 Heater Core: Service and Repair Without Air Conditioning 1. Disconnect battery ground cable and drain cooling system. 2. Disconnect heater hoses from heater core. Plug core outlets to prevent coolant spillage. 3. Disconnect electrical connections at blower motor and resistor. 4. Detach heater wiring from clip at blower housing cover. 5. Remove blower housing cover attaching screws, then remove blower housing cover. 6. Remove heater core. 7. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Lamps and Indicators - Cooling System > Coolant Level Indicator Lamp > Component Information > Description and Operation Coolant Level Indicator Lamp: Description and Operation DESCRIPTION This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. OPERATION Some vehicles use a buzzer or indicator lamp to convey a low coolant level condition. The buzzer or lamp is activated by a sensor, located in the radiator, when the coolant level becomes one quart low, or more. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Lamps and Indicators - Cooling System > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator Off W/Coolant Level Low Fig. 97 Chart 6: Low Coolant Level Indicator Inoperative W/Coolant Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Lamps and Indicators - Cooling System > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low > Page 2543 Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator On w/Coolant Level OK Fig. 96 Chart 5: Low Coolant Level Indicator On W/Coolant Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Lamps and Indicators - Cooling System > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Page 2544 Coolant Level Indicator Lamp: Service and Repair This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Lamps and Indicators - Cooling System > Temperature Gauge > Component Information > Description and Operation Temperature Gauge: Description and Operation DESCRIPTION This temperature indicating system consists of a sending unit, located on the cylinder head, electrical temperature gauge and an instrument voltage regulator. OPERATION As engine temperature increases or decreases, the resistance of the sending unit changes, in turn controlling current flow through the gauge. When engine temperature is low sending unit resistance is high, current flow through the gauge is restricted, and the gauge pointer remains against the stop or moves very little. As engine temperature increases sending unit resistance decreases and current flow through the gauge increases, resulting in increased pointer movement. Troubleshooting for the electrical temperature indicating system is the same as for the electrical oil pressure indicating system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Lamps and Indicators - Cooling System > Temperature Gauge > Component Information > Description and Operation > Page 2548 Temperature Gauge: Testing and Inspection Fig. 104 Chart 2: Engine Coolant Temperature Gauge Inoperative Or Inaccurate Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Lamps and Indicators - Cooling System > Temperature Warning Lamp/Indicator, Engine Cooling > Component Information > Description and Operation Temperature Warning Lamp/Indicator: Description and Operation DESCRIPTION If the red light is not lit when the engine is being cranked, check for a burned out bulb, an open in the light circuit, or a defective ignition switch. If the red light is lit when the engine is running, check the wiring between light and switch for a ground, temperature switch defective, or overheated cooling system. As a test circuit to check whether the red bulb is functioning properly, a wire which is connected to the ground terminal of the ignition switch is tapped into its circuit. When the ignition is in the start engine cranking position, the ground terminal is grounded inside the switch and the red bulb will be lit. When the engine is started and the ignition switch is in the on position, the test circuit is opened and the bulb is then controlled by the temperature switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators Radiator: Technical Service Bulletins Cooling System, A/C - Aluminum Heater Cores/Radiators INFORMATION Bulletin No.: 05-06-02-001A Date: July 16, 2008 Subject: Information On Aluminum Heater Core and/or Radiator Replacement Models: 2005 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2003-2005 HUMMER H2 Supercede: This bulletin is being revised to update the Warranty Information. Please discard Corporate Bulletin Number 05-06-02-001 (Section 06 - Engine/Propulsion System). Important: 2004-05 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX-COOL(R). Refer to the flushing procedure explained later in this bulletin. The following information should be utilized when servicing aluminum heater core and/or radiators on repeat visits. A replacement may be necessary because erosion, corrosion, or insufficient inhibitor levels may cause damage to the heater core, radiator or water pump. A coolant check should be performed whenever a heater core, radiator, or water pump is replaced. The following procedures/ inspections should be done to verify proper coolant effectiveness. Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if the radiator cap or surge tank cap is removed while the engine and radiator are still hot. Important: If the vehicle's coolant is low, drained out, or the customer has repeatedly added coolant or water to the system, then the system should be completely flushed using the procedure explained later in this bulletin. Technician Diagnosis ^ Verify coolant concentration. A 50% coolant/water solution ensures proper freeze and corrosion protection. Inhibitor levels cannot be easily measured in the field, but can be indirectly done by the measurement of coolant concentration. This must be done by using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale), or equivalent, coolant tester. The Refractometer uses a minimal amount of coolant that can be taken from the coolant recovery reservoir, radiator or the engine block. Inexpensive gravity float testers (floating balls) will not completely analyze the coolant concentration fully and should not be used. The concentration levels should be between 50% and 65% coolant concentrate. This mixture will have a freeze point protection of -34 degrees Fahrenheit (-37 degrees Celsius). If the concentration is below 50%, the cooling system must be flushed. ^ Inspect the coolant flow restrictor if the vehicle is equipped with one. Refer to Service Information (SI) and/or the appropriate Service Manual for component location and condition for operation. ^ Verify that no electrolysis is present in the cooling system. This electrolysis test can be performed before or after the system has been repaired. Use a digital voltmeter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. Any voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is often an intermittent condition that occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused from a poorly grounded cooling fan or some other accessory and can be verified by watching the volt meter and turning on and off various accessories or engage the starter motor. Before using one of the following flush procedures, the coolant recovery reservoir must be removed, drained, cleaned and reinstalled before refilling the system. Notice: ^ Using coolant other than DEX‐COOL(R) may cause premature engine, heater core or radiator corrosion. In addition, the engine coolant may require changing sooner, at 30,000 miles (50,000 km) or 24 months, whichever occurs first. Any repairs would not be covered by your warranty. Always use DEX‐COOL(R) (silicate free) coolant in your vehicle. ^ If you use an improper coolant mixture, your engine could overheat and be badly damaged. The repair cost would not be covered by your warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core and other parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators > Page 2556 Flushing Procedures using DEX-COOL(R) Important: The following procedure recommends refilling the system with DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. This coolant is orange in color and has a service interval of 5 years or 240,000 km (150,000 mi). However, when used on vehicles built prior to the introduction of DEX-COOL(R), maintenance intervals will remain the same as specified in the Owner's Manual. ^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions. ^ If approved cooling system flush and fill machine is not available, drain the coolant and dispose of properly following the draining procedures in the appropriate Service Manual. Refill the system using clear, drinkable water and run the vehicle until the thermostat opens. Repeat and run the vehicle three (3) times to totally remove the old coolant or until the drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with DEX‐COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M, following the refill procedures in the appropriate Service Manual. If a Service Manual is not available, fill half the capacity of the system with 100% DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. Then slowly add clear, drinkable water (preferably distilled) to the system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and reverify the coolant level. If necessary, add clean water to restore the coolant to the appropriate level. Once the system is refilled, reverify the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. The concentration levels should be between 50% and 65%. Flushing Procedures using Conventional Silicated (Green Colored) Coolant Important: 2004-2005 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX‐COOL(R). The Aveo and Wave are filled with conventional, silicated engine coolant that is blue in color. Silicated coolants are typically green in color and are required to be drained, flushed and refilled every 30,000 miles (48,000 km). The Aveo and Wave are to be serviced with conventional, silicated coolant. Use P/N 12378560 (1 gal) (in Canada, use P/N 88862159 (1 L). Refer to the Owner's Manual or Service Information (SI) for further information on OEM coolant. Important: Do not mix the OEM orange colored DEX-COOL(R) coolant with green colored coolant when adding coolant to the system or when servicing the vehicle's cooling system. Mixing the orange and green colored coolants will produce a brown coolant which may be a customer dissatisfier and will not extend the service interval to that of DEX-COOL(R). Conventional silicated coolants offered by GM Service and Parts Operations are green in color. ^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions. ^ If approved cooling systems flush and fill machine is not available, drain coolant and dispose of properly following the draining procedures in appropriate Service Manual. Refill the system using clear, drinkable water and run vehicle until thermostat opens. Repeat and run vehicle three (3) times to totally remove old coolant or until drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with a good quality ethylene glycol base engine coolant, P/N 12378560, 1 gal (in Canada, use P/N 88862159 1 L), conforming to GM specification 1825M, or recycled coolant conforming to GM specification 1825M, following the refill procedures in the appropriate Service Manual. If a Service Manual is not available, fill half the capacity of the system with 100% good quality ethylene glycol base (green colored) engine coolant, P/N 12378560 1 gal., (in Canada, use P/N 88862159 1 L) conforming to GM specification 1825M. Then slowly add clear, drinkable water (preferably distilled) to system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and recheck coolant level. If necessary, add clean water to restore coolant to the appropriate level. Once the system is refilled, recheck the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. Concentration levels should be between 50% and 65%. Parts Information Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators > Page 2557 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators > Page 2558 Radiator: Technical Service Bulletins Cooling - Radiator Repair/Replacement Guidelines File In Section: 06 - Engine/Propulsion System Bulletin No.: 99-06-02-017 Date: October, 1999 INFORMATION Subject: Radiator Repair/Replacement Guidelines Models: 2000 and Prior Passenger Cars and Trucks If repair of an aluminum/plastic radiator is required, it is recommended that the following guidelines be followed: For Vehicles Under Warranty For aluminum/plastic radiators that have damage to the face of the core including bent fins, punctures, cuts, leaking tubes or header tubes, the aluminum radiator core section should be replaced with a new one. In these cases, if both of the plastic tanks are not damaged, they can be reused with the new core. If one or both of the plastic tanks are damaged along with the core, it is recommended that a complete new radiator assembly be installed. Warranty repairs for leaks at the tank to header (gasket leaks), broken/cracked plastic tanks, cross threaded or leaking oil coolers should be repaired without replacing the complete radiator. This type of repair should be handled by the radiator repair facility in your area. Many of these radiator repair facilities are members of the National Automotive Radiator Service Association (NARSA) who follow industry and General Motors guidelines when repairing radiators. These facilities have the special tools, tanks and pressurizing equipment needed to properly test the repaired radiator prior to returning it to the dealership. Many of these facilities receive the repair components directly from General Motors. The sublet expense for a new radiator or the repair of the radiator under warranty should be handled following normal procedures. For Vehicles No Longer Under Warranty The GM released epoxy repair kit referenced in previous publications is no longer available. Repairs to the radiator, rather than replacement, is strictly at the owner's discretion. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Locations > Brace Radiator Support Front Of Radiator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Locations > Brace Radiator Support > Page 2561 Rear Side Radiator Support, Coolant Fans Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Locations > Brace Radiator Support > Page 2562 LH Radiator Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Radiator > Component Information > Locations > Page 2563 Radiator: Service and Repair 1. Disconnect battery ground cable, then remove air intake duct and resonator. 2. Drain coolant into suitable containers through valve located in left radiator end tank. 3. Disconnect engine coolant hoses from radiator, then remove engine cooling fans. 4. Disconnect and plug transmission cooler and engine oil cooler lines, if equipped. 5. Disconnect coolant recovery reservoir, then remove upper mounting panel if not equipped with mechanical fan. 6. Remove radiator. 7. Reverse procedure to install, noting the following. a. Ensure radiator is properly seated into lower mount cushions. b. Torque transmission cooler line fittings to 17 ft. lbs. and if equipped with an engine oil cooler torque fittings to 18 ft. lbs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Relays and Modules - Cooling System > Radiator Cooling Fan Motor Relay > Component Information > Locations Radiator Cooling Fan Motor Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Relays and Modules - Cooling System > Radiator Cooling Fan Motor Relay > Component Information > Locations > Page 2568 Engine Cooling Fan Relay Primary, Secondary Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Sensors and Switches - Cooling System > Coolant Level Sensor > Component Information > Locations Rear Side Radiator Support, Coolant Fans Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications Coolant Temperature Sensor/Switch (For Computer): Specifications Engine Coolant Temperature (ECT) Sensor ................................................................................................................................................ 23 Nm (17 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2577 Coolant Temperature Sensor/Switch (For Computer): Locations Left Front Of Engine The engine coolant temperature sensor is located near water pump. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2578 Coolant Temperature Sensor/Switch (For Computer): Description and Operation Engine Coolant Temperature Sensor The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) immersed in the engine coolant stream. Low coolant temperature produces a high resistance while high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the ECT through a resistor in the PCM and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage. the PCM knows the engine coolant temperature. Engine coolant temperature affects most systems the PCM controls. A failure in the ECT circuit should set either a Diagnostic Trouble Code (DTC) 14 or 15. Remember these DTCs indicate a failure in the engine coolant temperature sensor circuit, so proper use of the chart will lead to either repairing a wiring problem or replacing the sensor to properly repair a problem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2579 Coolant Temperature Sensor/Switch (For Computer): Service and Repair Engine Coolant Temperature Sensor IMPORTANT: Care must be taken when handling engine coolant (ECT) temperature sensor. Damage to engine coolant sensor will affect proper operation of the fuel injection system. REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Relieve coolant pressure. 3. Electrical connector. 4. Carefully back out sensor. INSTALL OR CONNECT 1. Coat threads with sealer. 2. Install sensor in engine. 3. Torque to 23 Nm (17 ft lb). 4. Connect electrical connector. 5. Refill lost coolant. 6. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Radiator Cooling Fan Temperature Sensor / Switch > Component Information > Locations Radiator Cooling Fan Temperature Sensor / Switch: Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Sensors and Switches - Cooling System > Engine - Coolant Temperature Sensor/Switch > Temperature Sensor (Gauge) > Component Information > Locations Temperature Sensor (Gauge): Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Temperature Gauge > Component Information > Description and Operation Temperature Gauge: Description and Operation DESCRIPTION This temperature indicating system consists of a sending unit, located on the cylinder head, electrical temperature gauge and an instrument voltage regulator. OPERATION As engine temperature increases or decreases, the resistance of the sending unit changes, in turn controlling current flow through the gauge. When engine temperature is low sending unit resistance is high, current flow through the gauge is restricted, and the gauge pointer remains against the stop or moves very little. As engine temperature increases sending unit resistance decreases and current flow through the gauge increases, resulting in increased pointer movement. Troubleshooting for the electrical temperature indicating system is the same as for the electrical oil pressure indicating system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Temperature Gauge > Component Information > Description and Operation > Page 2589 Temperature Gauge: Testing and Inspection Fig. 104 Chart 2: Engine Coolant Temperature Gauge Inoperative Or Inaccurate Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Temperature Warning Lamp/Indicator, Engine Cooling > Component Information > Description and Operation Temperature Warning Lamp/Indicator: Description and Operation DESCRIPTION If the red light is not lit when the engine is being cranked, check for a burned out bulb, an open in the light circuit, or a defective ignition switch. If the red light is lit when the engine is running, check the wiring between light and switch for a ground, temperature switch defective, or overheated cooling system. As a test circuit to check whether the red bulb is functioning properly, a wire which is connected to the ground terminal of the ignition switch is tapped into its circuit. When the ignition is in the start engine cranking position, the ground terminal is grounded inside the switch and the red bulb will be lit. When the engine is started and the ignition switch is in the on position, the test circuit is opened and the bulb is then controlled by the temperature switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Thermostat, Engine Cooling > Component Information > Specifications Thermostat: Specifications Coolant Capacity, Qts........................................................................................................................... ............................................................................ [12] Radiator Cap Relief Pressure, psi.................... .............................................................................................................................................................. ...... 15 Thermo. Opening Temp. °F...................................................................................................... ........................................................................................ 185 [12] Less heavy duty radiator, 14.3 qts., w/ heavy duty radiator, 14.6 qts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Thermostat, Engine Cooling > Component Information > Specifications > Page 2596 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Thermostat, Engine Cooling > Component Information > Specifications > Page 2597 Thermostat: Testing and Inspection Fig. 1 Thermostat. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Thermostat, Engine Cooling > Component Information > Specifications > Page 2598 Thermostat: Service and Repair Remove or Disconnect 1. Battery negative cable. 2. Air resonator and intake air duct. 3. Open coolant drain valve, located in the left-hand radiator end tank, and drain engine coolant. 4. Close coolant drain valve. 5. Radiator outlet hose and clamp from thermostat housing (14). 6. Bolts/screws (15). 7. Thermostat housing (14). 8. Thermostat (17) and gasket (16). Clean ^ Gasket surfaces of thermostat housing (14) and water pump (55). Install or Connect 1. Thermostat (17) and new gasket (16). 2. Thermostat housing (14). 3. Bolts/screws (15). Tighten Bolts/screws (15) to 28 Nm (21 lb. ft.). 4. Radiator outlet hose and clamp to thermostat housing (14). 5. Air intake duct and air resonator. 6. Add engine coolant. 7. Battery negative cable. Inspect ^ For leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly Water Pump: Service and Repair Coolant Pump Driveshaft Assembly This Article has been updated with TSB No. 57-61-28 COOLANT PUMP DRIVESHAFT ASSEMBLY Fig. 23 Water Pump & Thermostat Replacement TOOLS REQUIRED: ^ J 39243 Driven Gear Assembly Remover ^ J 41546 Driven Gear Assembly Installer ^ J 39089 Coolant Pump Shaft 0-Ring Protector Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2603 REMOVE OR DISCONNECT 1. Engine front cover assembly. 2. Rotate crankshaft assembly until timing marks punched on crankshaft sprocket and camshaft sprocket are aligned. 3. Camshaft sprocket bolts/screws. 4. Camshaft sprocket and timing chain assembly. NOTICE: Do not turn the crankshaft assembly after the timing chain has been removed to prevent damage to piston assemblies or valves. 5. Coolant pump bearing retainer bolts/screws and coolant pump driveshaft assembly using J 39243. ^ Remove and discard 0-ring from coolant pump drive-shaft assembly. INSTALL OR CONNECT 1. Coolant pump drive shaft assembly using J 39092. 2. Coolant pump bearing retainer bolts/screws. TIGHTEN ^ Coolant pump bearing retainer bolts/screws to 12 Nm (108 lb. in.). 3. Camshaft sprocket and timing chain assembly. ^ Camshaft sprocket and coolant pump driveshaft gears must mesh, or damage to camshaft retainer could occur. 4. Camshaft sprocket bolts/screws. ^ Make sure that camshaft and crankshaft timing marks align. TIGHTEN ^ Camshaft sprocket bolts/screws to 28 Nm (21 lb. ft.). 5. New 0-ring to coolant pump driveshaft assembly using J 39089. 6. Engine front cover assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2604 Water Pump: Service and Repair Water/Coolant Pump WATER PUMP REPLACEMENT Fig. 17 Water Pump Replacement REMOVAL PROCEDURE The camshaft sprocket gear drives the water pump by using a drive shaft and coupling. Keep the ignition wires connected to the distributor until the water pump is removed and all the coolant has been drained. 1. Drain the engine coolant. 2. Remove the air cleaner resonator bracket nuts, if equipped with a mechanical fan. 3. If the vehicle is equipped with a mechanical fan, remove the air cleaner resonator by loosening the clamp and sliding the resonator off the studs. 4. If the vehicle is equipped with a mechanical fan, remove the air intake duct. 5. If the vehicle is equipped with a mechanical fan, remove the radiator fan upper shroud. 6. If the vehicle is equipped with a mechanical fan, remove the fan belt from the tensioner. 7. If the vehicle is equipped with a mechanical fan, remove the fan blade clutch nuts and the fan blade with the clutch attached. 8. Remove the engine coolant and the heater hoses from the water pump. 9. If the vehicle is equipped with a mechanical fan, remove the fan pulley. 10. If the vehicle is equipped with a mechanical fan, remove the coolant fan pulley bracket nuts. 11. If the vehicle is equipped with a mechanical fan, remove the coolant fan pulley bracket. 12. Remove the electrical connector from the coolant sensor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2605 13. Remove the secondary air injection pump and bracket. 14. Remove the water pump bolts and the stud. 15. Remove the water pump and gaskets. 16. Remove the water pump driveshaft coupling and the seals. ^ Discard the seals. CLEAN ^ The water pump gasket surfaces. ^ The water pump bolts. ^ The coolant fan pulley bracket studs, if removed. INSTALLATION PROCEDURE 1. Install the water pump driveshaft coupling and the new seals. 2. Install the water pump and the gaskets. 3. Install the water pump bolts and the stud. TIGHTEN ^ Bolts and the stud to 41 Nm (30 lb ft). NOTICE: Use the correct fastener in the correct location. Replacement fasteners must be the correct part number for that application. Fasteners requiring replacement or fasteners requiring the use of thread locking compound or sealant are identified in the service procedure. Do not use paints, lubricants, or corrosion inhibitors on fasteners or fastener joint surfaces unless specified. These coatings affect fastener torque and joint clamping force and may damage the fastener. Use the correct tightening sequence and specifications when installing fasteners in order to avoid damage to parts and systems. 4. Install the secondary air injection pump and bracket. Refer to Refer to Air Pump in Engine Controls. 5. Install the electrical connector to the coolant sensor. 6. Install the coolant fan pulley bracket, if removed. 7. Install the coolant fan pulley bracket nuts, if removed. TIGHTEN ^ Nuts to 50 Nm (37 lb ft). 8. Install the fan pulley, if removed. 9. Install the fan blade with the clutch attached and the nuts, if removed. TIGHTEN ^ Nuts to 26 Nm (19 lb ft). 10. Install the engine coolant hoses and the heater hoses to the water pump. 11. Install the fan belt to the tensioner if the fan belt has been removed. 12. Install the radiator fan upper shroud if the radiator fan upper shroud has been removed. 13. Install the air intake duct, if removed. 14. If the air cleaner resonator has been removed, install the air cleaner resonator by sliding the resonator over the studs and tightening the clamp until snug. 15. Install the air cleaner resonator bracket nuts, if removed. TIGHTEN ^ Nuts to 10 Nm (89 lb in). 16. Refill and bleed the cooling system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Cooling System > Water Pump > Component Information > Service and Repair > Coolant Pump Driveshaft Assembly > Page 2606 Water Pump: Service and Repair Water Pump Disassembly The OEM service manual does not provide water pump assembly service and repair information. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Exhaust System > Catalytic Converter > Component Information > Locations Catalytic Converter Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Exhaust System > Exhaust Manifold > Component Information > Service and Repair Exhaust Manifold: Service and Repair Fig. 3 Exhaust Manifold Installation 1. Remove warm up three-way catalytic converter and gasket from exhaust manifold. 2. Remove oil level indicator tube. 3. Remove secondary air injection pipe fitting from exhaust manifold. 4. Remove generator rear lower braces. 5. Remove exhaust manifold bolts/screws, studs and spacers, Fig. 3. 6. Remove exhaust manifold and gasket. 7. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Exhaust System > Muffler > Component Information > Technical Service Bulletins > Customer Interest for Muffler: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler Muffler: Customer Interest Exhaust System - Paint Peeling from Painted Muffler File In Section: 10 - Body Bulletin No.: 33-17-01A Date: December, 1997 Subject: Paint Peeling from Muffler (New Repair Paint Available) Models: 1993-98 Passenger Cars with Painted Mufflers This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 33-17-01 (Section 10 - Body). Condition Some owners may experience paint peeling from the muffler. Correction Clean and repaint the affected area using the following procedure and product. Important: DO NOT REPLACE COMPONENTS TO REPAIR THIS CONDITION. The exhaust system must be cold to begin this procedure. Material Required: * Wabash Products # KB-318-HHHS, available in pints or quarts as ready to spray material (no mixing required). Call Wabash Products, 1-800-326-7269 or 812-232-6097 for pricing and shipping information. Procedure On a cold exhaust system: 1. Raise vehicle on hoist. 2. While supporting exhaust with a transmission jack, remove the rear exhaust system hangers and lower the exhaust. 3. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 4. Wire brush the affected area to remove flaking paint and blow off with air. 5. Sand the affected area with # 80 to 150 grit sandpaper to remove rust, dirt or other contaminants. 6. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 7. Tape off the rear lower body panels and exhaust pipes forward of mufflers to protect from overspray. 8. Apply paint to affected area in several (6 to 8) thin coats (to prevent sags and runs) obtaining approximately 1 mil paint coverage. 9. Raise exhaust system with jack, reinstall exhaust hangers, lower vehicle and remove from hoist. ^ Allow 30 minutes drying time. 10. In a well ventilated area, start engine and allow to idle for up to 30 minutes until paint is cured and dry. Important: Some "smoking" will occur while curing the paint with the engine running. The paint can be heated and cured while driving, but be careful not to get the exhaust system wet during the first 30 minutes. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Exhaust System > Muffler > Component Information > Technical Service Bulletins > Customer Interest for Muffler: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler > Page 2622 Labor Material Operation Labor Time Allowance A6150 0.6 hr - Single Exhaust GC Add 0.2 hr - Dual Exhaust GC Important: While the above procedure and materials are correct for vehicles from 1993 to 1998, the Labor Operation and Time Allowance only pertains to vehicles in the Warranty period. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Exhaust System > Muffler > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Muffler: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler Muffler: All Technical Service Bulletins Exhaust System - Paint Peeling from Painted Muffler File In Section: 10 - Body Bulletin No.: 33-17-01A Date: December, 1997 Subject: Paint Peeling from Muffler (New Repair Paint Available) Models: 1993-98 Passenger Cars with Painted Mufflers This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 33-17-01 (Section 10 - Body). Condition Some owners may experience paint peeling from the muffler. Correction Clean and repaint the affected area using the following procedure and product. Important: DO NOT REPLACE COMPONENTS TO REPAIR THIS CONDITION. The exhaust system must be cold to begin this procedure. Material Required: * Wabash Products # KB-318-HHHS, available in pints or quarts as ready to spray material (no mixing required). Call Wabash Products, 1-800-326-7269 or 812-232-6097 for pricing and shipping information. Procedure On a cold exhaust system: 1. Raise vehicle on hoist. 2. While supporting exhaust with a transmission jack, remove the rear exhaust system hangers and lower the exhaust. 3. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 4. Wire brush the affected area to remove flaking paint and blow off with air. 5. Sand the affected area with # 80 to 150 grit sandpaper to remove rust, dirt or other contaminants. 6. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 7. Tape off the rear lower body panels and exhaust pipes forward of mufflers to protect from overspray. 8. Apply paint to affected area in several (6 to 8) thin coats (to prevent sags and runs) obtaining approximately 1 mil paint coverage. 9. Raise exhaust system with jack, reinstall exhaust hangers, lower vehicle and remove from hoist. ^ Allow 30 minutes drying time. 10. In a well ventilated area, start engine and allow to idle for up to 30 minutes until paint is cured and dry. Important: Some "smoking" will occur while curing the paint with the engine running. The paint can be heated and cured while driving, but be careful not to get the exhaust system wet during the first 30 minutes. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Engine, Cooling and Exhaust > Exhaust System > Muffler > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Muffler: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler > Page 2628 Labor Material Operation Labor Time Allowance A6150 0.6 hr - Single Exhaust GC Add 0.2 hr - Dual Exhaust GC Important: While the above procedure and materials are correct for vehicles from 1993 to 1998, the Labor Operation and Time Allowance only pertains to vehicles in the Warranty period. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage Engine Control Module: Technical Service Bulletins Engine Controls - Aftermarket Accessory Usage INFORMATION Bulletin No.: 04-06-04-054B Date: November 18, 2010 Subject: Info - Non-GM Parts and Accessories (Aftermarket) Models: 2011 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add model years and update to the new U.S. Fixed Operation Manager (FOM) and Canada Warranty Manager (WM) names. Please discard Corporate Bulletin Number 04-06-04-054A (Section 06 - Engine/Propulsion System). The recent rise and expansion of companies selling non-GM parts and accessories has made it necessary to issue this reminder to dealers regarding GM's policy on the use and installation of these aftermarket components. When a dealer is performing a repair under the New Vehicle Limited Warranty, they are required to use only genuine GM or GM-approved parts and accessories. This applies to all warranty repairs, special policy repairs or any repairs paid for by GM. Parts and accessories advertised as being "the same" as parts manufactured by GM, but not sold through GM, do not qualify for use in warranty repairs, special policy repairs or any repairs paid for by GM. During a warranty repair, if a GM original equipment part is not available through GM Customer Care and Aftersales (GM CC&A;), ACDelco(R) distributors, other GM dealers or approved sources, the dealer is to obtain comparable, non-GM parts and clearly indicate, in detail, on the repair order the circumstances surrounding why non-GM parts were used. The dealer must give customers written notice, prior to the sale or service, that such parts or accessories are not marketed or warranted by General Motors. It should also be noted that dealers modifying new vehicles and installing equipment, parts and accessories obtained from sources not authorized by GM are responsible for complying with the National Traffic and Motor Vehicle Safety Act. Certain non-approved parts or assemblies, installed by the dealer or its agent not authorized by GM, may result in a change to the vehicle's design characteristics and may affect the vehicle's ability to conform to federal law. Dealers must fully understand that non-GM approved parts may not have been validated, tested or certified for use. This puts the dealer at risk for potential liability in the event of a part or vehicle failure. If a GM part failure occurs as the result of the installation or use of a non-GM approved part, the warranty will not be honored. A good example of non-authorized modification of vehicles is the result of an ever increasing supply of aftermarket devices available to the customer, which claim to increase the horsepower and torque of the Duramax(TM) Diesel Engines. These include the addition of, but are not limited to one or more of the following modifications: - Propane injection - Nitrous oxide injection - Additional modules (black boxes) that connect to the vehicle wiring systems - Revised engine calibrations downloaded for the engine control module - Calibration modules which connect to the vehicle diagnostic connector - Modification to the engine turbocharger waste gate Although the installation of these devices, or modification of vehicle components, can increase engine horsepower and torque, they may also negatively affect the engine emissions, reliability and/or durability. In addition, other powertrain components, such as transmissions, universal joints, drive shafts, and front/rear axle components, can be stressed beyond design safety limits by the installation of these devices. General Motors does not support or endorse the use of devices or modifications that, when installed, increase the engine horsepower and torque. It is because of these unknown stresses, and the potential to alter reliability, durability and emissions performance, that GM has adopted a policy that prevents any UNAUTHORIZED dealer warranty claim submissions to any remaining warranty coverage, to the powertrain and driveline components whenever the presence of a non-GM (aftermarket) calibration is confirmed - even if the non-GM control module calibration is subsequently removed. Refer to the latest version of Bulletin 09-06-04-026 (V8 Gas Engines) or 06-06-01-007 (Duramax(TM) Diesel Engines) for more information on dealer requirements for calibration verification. These same policies apply as they relate to the use of non-GM accessories. Damage or failure from the use or installation of a non-GM accessory will not be covered under warranty. Failure resulting from the alteration or modification of the vehicle, including the cutting, welding or disconnecting of the vehicle's original equipment parts and components will void the warranty. Additionally, dealers will NOT be reimbursed or compensated by GM in the event of any legal inquiry at either the local, state or federal level that Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2636 results from the alteration or modification of a vehicle using non-GM approved parts or accessories. Dealers should be especially cautious of accessory companies that claim the installation of their product will not void the factory warranty. Many times these companies have even given direction on how to quickly disassemble the accessory in an attempt to preclude the manufacturer from finding out that is has been installed. Any suspect repairs should be reviewed by the Fixed Operations Manager (FOM), and in Canada by the Warranty Manager (WM) for appropriate repair direction. If it is decided that a goodwill repair is to be made on the vehicle, even with the installation of such non-GM approved components, the customer is to be made aware of General Motors position on this issue and is to sign the appropriate goodwill documentation required by General Motors. It is imperative for dealers to understand that by installing such devices, they are jeopardizing not only the warranty coverage, but also the performance and reliability of the customer's vehicle. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2637 Engine Control Module: Technical Service Bulletins PROM - Reprogram Using Off Board Program Adapter File In Section: 6E - Engine Fuel & Emission Bulletin No.: 73-65-13 Date: March, 1997 INFORMATION Subject: Reprogramming Capability using the Off Board Programming Adapter Models: 1993-97 Passenger Cars and Trucks (Applicable Reprogrammable Vehicles) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2638 The General Motors vehicles contain Electronically Reprogrammable Devices (i.e. PCM, VCM, ECM). These vehicles cannot be programmed through PROM replacement, however service programming capability is available through the Tech 1/1A, Tech 2 and Techline terminals via direct or remote programming. The Environmental Protection Agency (EPA) has requested that all new vehicle manufacturers ensure their dealers/retailers are aware that they are responsible for providing customers access to reprogramming services at a reasonable cost and in a timely manner. Although programming of controllers has become a common service practice at GM dealers/retailers, the EPA has received reports from consumers and the aftermarket repair industry that they were unable to purchase a new (programmed) Electronically Reprogrammable Device (ERD) over-the-counter. As a result, on August 1, 1995, the Federal Government issued a regulation requiring all manufacturers to make available reprogramming to the independent aftermarket by December 1, 1997. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2639 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2640 Today, the Off Board Programming Adapter (OBPA) is used to reprogram ERD's sold over-the-counter. For all practical purposes, the OBPA takes the place of the vehicle when the vehicle is not available. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2641 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2642 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2643 The list of dealerships/retailers currently own the OBPA (see Attachments 1 - 3). These locations are equipped to provide over-the-counter preprogrammed ERD's. The hardware required to perform reprogramming in addition to the OBPA is a Techline terminal, Tech 1/1A and associated cables and adapters. THE TECH 2 SHOULD NOT BE USED WITH THE OBPA AT THIS TIME BECAUSE OF INADEQUATE OBPA GROUNDING. The current OBPA can support reprogramming on all late model General Motor's vehicles except: ^ Premium V-8's ^ 1996 Diesel Truck ^ Cadillac Catera Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 2644 ^ All 1997 programmable vehicles (requires use of the Tech 2) A modification to the OBPA is being offered by Kent-Moore to support these additional vehicles and to allow reprogramming using the Tech 2. The revisions to the OBPA for the Tech 2 is very important as the Tech 2 is the only tool used for service programming for 1997 and future vehicles. To have the modifications performed, contact Kent-Moore at (800) 345-2233. The revisions (part number J 41207 REV-C) are free of charge for GM dealerships/retailers. A dealership/retailer can purchase the OBPA by contacting Kent-Moore (part number J 41207-C). Support on how to use the OBPA is provided by the Techline Customer Support Center (TCSC) at (800) 828-6860 (English) or (800) 503-3222 (French). If you need to purchase an OBPA and/or cable, contact Kent-Moore at (800) 345-2233. The OBPA retails for $695.00 (includes all revisions 1-4) under part number J 41207-C. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Page 2645 Engine Control Module: Specifications Powertrain Control Module (PCM) .............................................................................................................................................................. 3 Nm (26 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations PCM Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 2648 Engine Control Module: Connector Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 2649 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 2650 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 2651 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions Engine Control Module: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2654 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2655 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2656 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2657 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2658 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2659 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2660 Engine Control Module: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2661 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2662 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2663 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2664 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2665 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2666 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2667 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2668 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2669 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2670 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2671 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2672 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2673 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2674 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2675 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2676 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2677 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2678 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2679 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2680 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2681 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2682 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2683 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2684 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2685 Engine Control Module: Connector Views Powertrain Control Module (PCM): A Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2686 Powertrain Control Module (PCM): B Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2687 Powertrain Control Module (PCM): C Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2688 Powertrain Control Module (PCM): D Pinout Information PCM Connectors CAUTION: Do not backprobe Powertrain Control Module (PCM) connectors! The connectors are sealed for operation in an underhood environment. Backprobing may damage the seal which could eventually cause the connector to fail due to corrosion. This information applies to the PCM connector charts in the next four images. These charts may be used with the J 39700-A breakout box in conjunction with J 39700-110 and J 39700-140 cables and high impedance digital multimeter J 39200 to obtain voltage present for each circuit listed. Install the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2689 breakout box between the PCM connectors and the PCM. The breakout box PIN numbers correspond with the PCM connector PIN numbers. Voltage may vary slightly, but should be very close. Certain exceptions are called out in the chart legend below. The following conditions must be met before checking typical voltages: Key "ON": ^ DVM negative (black) lead connected to a known good ground. ^ Scan tool "NOT" installed. ^ All accessories "OFF." ^ Battery fully charged. Engine Running: ^ All conditions listed above. ^ Engine at normal operating temperature. ^ Engine at idle/closed throttle/operating in "Closed Loop." ^ In park or neutral. CHART LEGEND (1) Less than .5 volt when system enabled. (2) Battery voltage for first two seconds with ignition "ON." (3) Varies. (4) Varies with temperature. (5) Battery voltage when in gear. (6) Less than .5 volt with brake pedal applied. (7) Battery voltage with A/C "ON." (8) Varies with altitude. (9) Less than .5 volt with high power steering load. (*) Less than .5 volt. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2690 Connector "A" RED Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2691 Connector "B" BLACK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2692 Connector "C" GREY/CLEAR Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 2693 Connector "D" BLUE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Page 2694 Engine Control Module: Description and Operation PCM Connectors The Powertrain Control Module (PCM) is the control center of the fuel injection system. It constantly looks at the information from various sensors and controls the systems that affect vehicle performance. The PCM also performs a diagnostic function check of the system. It can recognize operational problems and alert the driver through the Malfunction Indicator Lamp (MIL) "Service Engine Soon" and store Diagnostic Trouble Code(s) (DTC) which identify the problem areas to aid the technicians making repairs. The PCM supplies 5 or 12 volts to power various sensors or switches. This is done through resistances in the PCM which are so high in value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading because its resistance is too low. Therefore, the use of a 10 megohm input impedance digital voltmeter (J 39200) is required to assure accurate voltage readings. Refer to Computers and Controls / System Diagnosis / Flow of Diagnosis / "Strategy Based Diagnostics" for more information on using the diagnostic function of the PCM. MEMORY There are three types of memory storage within the PCM: Read Only Memory (ROM), Random Access Memory (RAM) and Electrically Erasable Programmable Read Only Memory (EEPROM). ROM Read Only Memory (ROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The ROM contains the overall control programs. Once the ROM is programmed, it cannot be changed. The ROM memory is non-erasable, and does not need power to be retained. RAM Random Access Memory (RAM) is the microprocessor "scratch pad." The processor can write into, or read from this memory as needed. This memory is erasable and needs a constant supply of voltage to be retained. If the voltage is lost, the memory is lost. EEPROM Electrically Erasable Programmable Read Only Memory (EEPROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The EEPROM contains the overall control algorithms. The EEPROM can be reprogrammed by using the Tech 1 scan tool or other Decline terminal/equipment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Component Tests and General Diagnostics Engine Control Module: Component Tests and General Diagnostics To display diagnostic trouble codes, use a Tech 1 (or equivalent scanner). Grounding the DLC will NOT flash Diagnostic Trouble Code(s) (DTC), but will enable most outputs when the ignition is "ON" engine "OFF." Grounding the Data Link Connector (DLC) while the engine is running will cause the Malfunction Indicator Lamp (MIL) to flash to indicate "Open" or "Closed Loop. This is referred to as Field Service Mode." To clear the DTCs from memory use the Tech 1 or: ^ ignition "OFF." ^ Disconnect the # 2 fuse (located in the underhood electrical center) for 30 seconds. Since the Powertrain Control Module (PCM) can have a failure which may affect only one circuit, following the diagnostic procedures in this section will determine which circuit has a problem and where it is. If a diagnostic chart indicates that the PCM connections or PCM is the cause of a problem and the PCM is replaced the Knock Sensor (KS) module must be transferred to the new PCM and the new PCM must then be programmed. If this does not correct the problem, one of the following may be the reason: ^ There is a problem with the PCM terminal connections. The diagnostic chart will say PCM connections or PCM. The terminals may have to be removed from the connector in order to check them properly. ^ The problem is intermittent. This means that the problem is not present at the time the system is being checked. In this case. Refer to Diagnosis by Symptom and make a careful physical inspection of all portions of the system involved. ^ Shorted solenoid, relay coil, or harness. Solenoids and relays are turned "ON" and "OFF" by the PCM using internal electronic switches called "drivers." A shorted solenoid, relay coil, or PCM harness will not damage the PCM but will cause the component to be inoperative. J 34636 or BT-8405 testers or equivalent provide a fast accurate means of checking for a shorted coil or a short to battery voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 2697 Engine Control Module: Service and Repair Removal Hardware Removal NOTE: To prevent internal Powertrain Control Module (PCM) damage, the ignition must be "OFF", when disconnecting or reconnecting power to the PCM. Remove or Disconnect: 1. Disconnect negative battery cable 2. Disconnect PCM mounting hardware 3. Disconnect PCM electrical connectors 4. Remove PCM from engine compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 2698 PCM With Knock Sensor Module 5. Remove PCM access cover Removing Knock Sensor Module From PCM 6. Remove knock sensor module from PCM Install or Connect: 1. Install knock sensor module and access cover 2. Install PCM in vehicle 3. Connect PCM electrical connectors 4. Connect PCM mounting hardware 5. Connect negative battery cable EEPROM Programming CAUTION:The software/calibration used for PCM reprogramming must match the vehicle application, or improper operation and/or damage may occur. ^ Ensure battery is charged ^ Turn ignition "ON" ^ Ensure connections to the Data Link Connector (DLC) and battery/cigar lighter are secure ^ Follow the most current Decline terminal/equipment instructions Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 2699 PCM Reprogramming Failure ^ Check PCM connections ^ Check Decline terminal/equipment for latest software version ^ Repeat reprogramming procedures. If it fails again, replace the PCM. The replacement PCM must be programmed. PCM Functional Check ^ Refer to System Diagnosis / Diagnostic System Check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Knock Sensor Module > Component Information > Locations PCM With Knock Sensor Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Computers and Control Systems > Knock Sensor Module > Component Information > Locations > Page 2703 Knock Sensor Module: Service and Repair PCM With Knock Sensor Module Removing Knock Sensor Module From PCM REMOVE OR DISCONNECT 1. Negative battery cable. 2. Powertrain Control Module (PCM) from mounting bracket (refer to PCM removal). 3. Knock sensor (KS) module access cover. 4. Knock sensor module. INSTALL OR CONNECT NOTICE: To prevent possible electrostatic discharge damage to the PCM and KS module, Do Not touch the connector pins or soldered components on the circuit board. 1. Knock senor module. 2. Access cover. 3. PCM to mounting bracket (refer to PCM installation). 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Emission Control Systems > Air Injection Pump Relay > Component Information > Locations Air Injection Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Emission Control Systems > Air Injection Pump Relay > Component Information > Locations > Page 2708 Air Injection Pump Relay: Description and Operation Chart C-6 The Powertrain Control Module (PCM) controls operation of the electric air pump relay which in turn controls air availability to the air injection system. The PCM completes the ground to the coil side of the relay. The relay in turn activates the electric air pump and the integral stop valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Locations Fuel Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions Fuel Pump Relay: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2715 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2716 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2717 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2718 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2719 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2720 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2721 Fuel Pump Relay: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2722 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2723 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2724 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2725 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2726 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2727 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2728 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2729 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2730 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2731 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2732 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2733 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2734 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2735 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2736 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2737 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2738 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2739 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2740 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2741 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2742 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2743 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2744 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 2745 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Page 2746 Fuel Pump Relay: Description and Operation When the ignition switch is turned to the "ON" position (before engaging starter), the energizes the fuel pump relay for two seconds causing the fuel pump to pressurize the fuel system. If the Powertrain Control Module (PCM) does not receive ignition reference pulses (engine cranking or running) within two seconds, it shuts "OFF" the fuel pump relay, causing the fuel pump to stop. As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Page 2747 Fuel Pump Relay: Service and Repair Fuel Pump (Circuit Opening) Relay REMOVE OR DISCONNECT 1. Underhood (U/H) electrical center cover. 2. Fuel pump relay. INSTALL OR CONNECT 1. Fuel pump relay. 2. Underhood (U/H) electrical center cover. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Specifications Ignition Control Module: Specifications Ignition Coil Assembly Bolt / Screw ........................................................................................................................................................... 25 Nm (18 lb ft.) Ignition Coil Assembly Stud ................................................................................................................. ...................................................... 25 Nm (18 lb ft.) Ignition Coil Module Bolt / Screw ............................................................................................................................................................. 1.7 Nm (15 lb in.) Replacement Coil to-Bracket Bolt / Screw ................................................................................................................................................. 2.8 Nm (25 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector Engine Left Side Upper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector > Page 2754 Ignition Control Module: Locations Ignition Module Ignition Coil Ignition Coil And Ignition Control Module The Ignition Control Module is located on the ignition coil bracket assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 2755 Ignition Control Module: Description and Operation Ignition Coil And Module Assembly Ignition Coil And Module The ignition coil/ignition control module assembly provides spark to the distributor assembly, timed by signals from the ECM. Power (B+) for the ignition coil primary circuit and the ignition control module is supplied by the ignition switch. The ECM combines the camshaft position information supplied by the distributor with other system parameters and calculates the required spark advance and coil dwell. The ECM signals the ignition control module, which turns on the primary current to the ignition coil by grounding the primary circuit, and then turns it off by removing the ground. When the primary current flow stops, high voltage induced in the ignition coil secondary winding becomes the spark voltage for the spark plug. The spark voltage is delivered to the distributor assembly through the coil output (secondary) wire, and then directed to the proper spark plug connector by the distributor rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 2756 Ignition Control Module: Service and Repair Ignition Coil Ignition Coil And Ignition Control Module Numbers used below refer to image caption. REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Four-terminal Powertrain Control Module (PCM) connector at ignition coil module. 3. Ignition coil wiring connectors. 4. Ignition coil harness. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Relays and Modules - Powertrain Management > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 2757 5. Studs (5). 6. Ignition coil / Ignition Control Module assembly (8). ^ Do not wipe silicone grease from bottom of ignition coil assembly (8) if it is to he reinstalled. DISASSEMBLE 1. Coil (10) from brackets (13 and 14) by drilling out rivets (9). 2. Bolts/screws (12). 3. Ignition control module (11). NOTICE: If a new ignition coil assembly is to be installed, a package of silicone grease will be included in the box. This grease is necessary for ignition coil assembly cooling. ASSEMBLE 1. Spread silicone grease on metal face of ignition control module (11) and on bracket (13) where it seats, and position ignition control module (11) to bracket (13). 2. Bolts / screws (12). Tighten ^ Bolts / screws (12) to 1.7 Nm (15 lb in.). 3. Coil (10) to brackets (13 and 14) using bolts / screws provided with replacement coil (10). Tighten ^ Bolts / screws to 2.8 Nm (25 lb in.). INSTALL OR CONNECT 1. Spread silicone grease on metal mounting face of ignition coil bracket (14) if necessary, and position ignition coil / Ignition Control module assembly (8) to cylinder head assembly. 2. Studs (5). Tighten ^ Studs (5) to 25 Nm (18 lb ft.). 3. Ignition coil harness. 4. Ignition coil wiring connectors. 5. Four terminal PCM connector to ignition coil module. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 2764 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2767 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2768 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2769 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2770 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2771 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2772 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2773 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2774 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2775 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2776 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2777 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2778 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2779 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2780 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2781 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2782 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2783 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2784 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2785 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2786 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2787 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2788 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2789 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2790 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2791 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2792 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2793 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2794 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2795 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2796 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2797 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2798 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 2799 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 2800 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2805 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2806 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2807 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2808 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2809 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2810 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2811 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2812 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2813 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2814 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2815 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2816 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2817 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2818 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2819 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2820 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2821 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2822 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2823 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2824 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2825 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2826 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2827 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2828 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2829 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2830 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2831 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2832 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2833 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2834 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2835 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications Coolant Temperature Sensor/Switch (For Computer): Specifications Engine Coolant Temperature (ECT) Sensor ................................................................................................................................................ 23 Nm (17 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2839 Coolant Temperature Sensor/Switch (For Computer): Locations Left Front Of Engine The engine coolant temperature sensor is located near water pump. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2840 Coolant Temperature Sensor/Switch (For Computer): Description and Operation Engine Coolant Temperature Sensor The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) immersed in the engine coolant stream. Low coolant temperature produces a high resistance while high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the ECT through a resistor in the PCM and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage. the PCM knows the engine coolant temperature. Engine coolant temperature affects most systems the PCM controls. A failure in the ECT circuit should set either a Diagnostic Trouble Code (DTC) 14 or 15. Remember these DTCs indicate a failure in the engine coolant temperature sensor circuit, so proper use of the chart will lead to either repairing a wiring problem or replacing the sensor to properly repair a problem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 2841 Coolant Temperature Sensor/Switch (For Computer): Service and Repair Engine Coolant Temperature Sensor IMPORTANT: Care must be taken when handling engine coolant (ECT) temperature sensor. Damage to engine coolant sensor will affect proper operation of the fuel injection system. REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Relieve coolant pressure. 3. Electrical connector. 4. Carefully back out sensor. INSTALL OR CONNECT 1. Coat threads with sealer. 2. Install sensor in engine. 3. Torque to 23 Nm (17 ft lb). 4. Connect electrical connector. 5. Refill lost coolant. 6. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2846 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2847 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2848 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2849 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2850 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2851 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2852 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2853 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2854 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2855 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2856 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2857 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2858 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2859 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2860 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2861 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2862 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2863 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2864 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2865 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2866 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2867 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2868 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2869 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2870 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2871 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2872 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2873 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2874 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2875 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2876 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Specifications Intake Air Temperature Sensor: Specifications Torque Valve Torque Valve Induction Air Sensor 44 in.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor Intake Air Temperature Sensor: Locations IAT Sensor The Intake Air Temperature (IAT) sensor is located in the air ducting, just forward of the throttle body assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 2882 Intake Air Temperature Sensor: Locations Intake Air Temperature (IAT) Sensor Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 2883 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions Intake Air Temperature Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2886 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2887 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2888 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2889 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2890 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2891 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2892 Intake Air Temperature Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2893 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2894 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2895 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2896 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2897 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2898 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2899 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2900 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2901 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2902 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2903 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2904 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2905 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2906 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2907 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2908 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2909 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2910 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2911 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2912 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2913 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2914 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2915 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2916 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2917 Intake Air Temperature (IAT) Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 2918 Intake Air Temperature Sensor: Description and Operation Engine Coolant Temperature (ECT) Sensor The Intake Air Temperature (IAT) sensor is a thermistor (a resistor which changes value based on temperature). It is mounted in the air intake duct. Low temperature produces a high resistance and high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the sensor through a resistor in the PCM and measures the voltage. The voltage will be high when the intake air is cold, and low when the intake manifold air is hot. By measuring the voltage, the PCM knows the intake air temperature. A failure in the IAT sensor circuit should set either a DTC 23 or DTC 25. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 2919 Intake Air Temperature Sensor: Service and Repair REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Electrical connector. 3. Carefully remove sensor from air duct. INSTALL OR CONNECT 1. Install sensor in engine. 2. Connect electrical connector. 3. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations > Page 2925 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2928 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2929 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2930 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2931 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2932 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2933 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2934 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2935 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2936 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2937 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2938 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2939 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2940 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2941 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2942 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2943 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2944 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2945 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2946 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2947 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2948 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2949 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2950 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2951 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2952 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2953 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2954 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2955 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2956 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2957 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2958 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2959 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 2960 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 2961 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 2962 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications MAP Sensor Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications > Page 2967 Manifold Pressure/Vacuum Sensor: Mechanical Specifications Manifold Absolute Pressure (MAP) Bolt ...................................................................................................................................................... 6 Nm (50 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Page 2968 Manifold Pressure/Vacuum Sensor: Locations MAP Sensor Location Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions Manifold Pressure/Vacuum Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2971 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2972 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2973 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2974 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2975 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2976 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2977 Manifold Pressure/Vacuum Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2978 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2979 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2980 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2981 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2982 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2983 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2984 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2985 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2986 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2987 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2988 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2989 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2990 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2991 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2992 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2993 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2994 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2995 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2996 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2997 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2998 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 2999 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3000 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3001 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3002 Map Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 3003 Manifold Pressure/Vacuum Sensor: Description and Operation MAP Sensor The Manifold Absolute Pressure (MAP) sensor is a pressure sensor that measures changes in intake manifold pressure. The pressure changes as a result of engine load and speed. The MAP sensor converts this to a voltage output. A closed throttle on engine coastdown would produce a relatively low MAP output while a wide-open throttle would produce a high MAP output voltage. This high output voltage is produced because the pressure inside the manifold is the same as outside the manifold, so you measure 100% of outside air pressure. Manifold Absolute Pressure (MAP) is inversely proportional to what you would measure on a vacuum gage. When manifold pressure is high vacuum is low. The MAP sensor is also used to measure barometric pressure under certain conditions which allows the Powertrain Control Module (PCM) to automatically adjust for different altitudes. The PCM sends a 5 volt reference signal to the MAP sensor. As the manifold pressure changes the electrical resistance of the MAP sensor also changes. By monitoring the sensor output voltage the PCM knows the manifold pressure. The PCM uses the MAP sensor to control ignition timing. The MAP sensor is also used for speed density fuel management. When the PCM detects a malfunction with the Mass Air Flow (MAF) sensor circuit the PCM will default to speed density. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 3004 Manifold Pressure/Vacuum Sensor: Service and Repair MAP Sensor Location REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Resonator. 3. Electrical connector. 4. Hold down bolts (2). 5. Sensor from intake manifold. INSTALL OR CONNECT 1. New sensor seal (lightly coated with clean engine oil). 2. Sensor into intake manifold. 3. Hold down bolts. 4. Torque to 6 Nm (50 lb in). 5. Connect electrical connector. 6. Resonator. 7. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Technical Service Bulletins > Oxygen Sensors - Silica Contamination Oxygen Sensor: Technical Service Bulletins Oxygen Sensors - Silica Contamination Model Year: 1981 Bulletin No: 81-I-37 File In Group: 60 Number: 11 Date: Feb. 81 Subject: Silica Contamination of Oxygen Sensors and Gelation of Oil. Models Affected: All Oxygen sensor performance can deteriorate if certain RTV silicone gasket materials are used. Other RTV's when used with certain oils, may cause gelation of the oil. The degree of performance severity depends on the type of RTV and application of the engine involved. Therefore, when repairing engines where this item is involved, it is important to use either cork composition gaskets or RTV silicone gasket material approved for such use. GMS (General Motors Sealant) or equivalent material can be used. GMS is available through GMPD with the following part numbers: 1052366 3 oz. 1052434 10.14 oz. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications Oxygen Sensor Output Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications > Page 3011 Oxygen Sensor: Mechanical Specifications Heated Oxygen Sensor (HO2S) .......................................................................................................... ......................................................... 41 Nm (30 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH Engine, Left Side Lower Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 3014 Lower Right Side Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 3015 HO2S Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions Oxygen Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3018 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3019 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3020 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3021 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3022 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3023 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3024 Oxygen Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3025 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3026 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3027 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3028 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3029 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3030 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3031 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3032 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3033 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3034 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3035 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3036 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3037 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3038 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3039 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3040 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3041 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3042 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3043 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3044 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3045 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3046 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3047 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3048 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3049 Oxygen Sensor: Electrical Diagrams Heated Oxygen Sensor (HO2S) Sensor Circuit. Right Heated Oxygen Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 3050 Oxygen Sensor: Description and Operation HO2S Cutaway Oxygen Sensor Element The Heated Oxygen Sensor (HO2S) is essentially a small variable battery; it has the ability to produce a low voltage signal that feeds information on engine exhaust oxygen content to the Powertrain Control Module (PCM). The PCM sends a reference signal of 450 mV. The reference signal serves to run the engine when it is in "Open Loop" mode of operation. When the air/fuel ratio is correct the PCM displays 450 mV. When the engine is operating with a rich air/fuel ratio, there is a reduction of free oxygen in the exhaust stream and the oxygen voltage rises above the reference voltage. The HO2S is constructed from a material (zirconia/platinum) that conducts electricity under certain conditions. At operating temperature, 315°C (60o° F), the element becomes a semiconductor. A platinum coating on the outer surface of the element stimulates further combustion of the exhaust gases right Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 3051 at the surface and this helps keep the element up to the desired temperature. The HO2S has an inter cavity which is filled with atmospheric (reference) air. The reference air has approximately 21% oxygen in it. In this electrical circuit this inter cavity is the positive (+) terminal. The outer surface of the element is exposed to the exhaust gas stream. It is the negative (-) or ground terminal. The oxygen concentration differences between the reference air and exhaust gases produce small voltages. A rich exhaust (excessive fuel) has almost no oxygen. When there is a large difference in the amount of oxygen touching the inside and outside surfaces, there is more conduction, and the sensor puts out a voltage signal above 600 mV. With lean exhaust (excessive oxygen) there is about two percent oxygen in the exhaust. This is a smaller difference in oxygen from the outside surfaces which results in less conduction and a voltage signal below 300 mV. The voltages are monitored and used by the PCM to "fine tune" the air/fuel ratio to achieve the ideal mixture desired. When the engine is running lean. the voltage drops below the reference voltage due to excess oxygen in the exhaust stream. The HO2S provides the feedback information for the "Closed Loop" operating mode of the fuel delivery system. The HO2S indicates to the PCM what is happening in the exhaust. It does not cause things to happen. It is a type of gage: Low voltage output = lean mixture = high oxygen content in exhaust; high voltage output = rich mixture = low oxygen content in the exhaust. An open Heated Oxygen Sensor (HO2S) circuit, should set Diagnostic Trouble Code (DTC) 13 or 63. A constant low voltage in the HO2S circuit could set a DTC 44 or 64. A constant high voltage in the circuit should set a DTC 45 or 65. DTCs 44. 45. 64, or 65 could also be set as a result of fuel system problems. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 3052 Oxygen Sensor: Service and Repair HO2S Location CAUTION: The Heated Oxygen Sensor (HO2S) uses a permanently attached pigtail and connector. This pigtail should not be removed from the oxygen sensor. Damage or removal of the pigtail or connector could affect proper operation of the oxygen sensor. ^ Take care when handling the oxygen sensor. The in-line electrical connector and louvered end must be kept free off grease, dirt or other contaminants. Also, avoid using cleaning solvents of any type. Be careful not to subject the sensor to sharp impact. REMOVAL: NOTICE: The HO2S may be difficult to remove when engine temperature is below 48° C (120° F). Excessive force may damage threads in exhaust pipe. 1. Disconnect the negative battery cable. 2. Raise vehicle. 3. Disconnect the oxygen sensor electrical connector. 4. Carefully remove the oxygen sensor. INSTALLATION: NOTICE: A special anti-seize compound is used on the oxygen sensor threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will already have the compound applied to the threads. If a sensor is removed from an engine, and, if for any reason it is to be reinstalled, the threads must have anti-seize compound applied before reinstallation. 1. Coat the threads of the HO2S with anti-seize compound P/N 5613695, or equivalent if necessary. 2. Install the sensor in the engine, and tighten to 41 Nm (30 ft lb). 3. Connect the electrical connector. 4. Lower vehicle. 5. Connect the negative battery cable. NOTICE: The system has a learning ability which allows it to make corrections for minor variations in the fuel system to improve driveability. When the battery is disconnected the computer's memory is cleared and the learning process has to begin all over again. A change may be noticed in the driving performance of the vehicle. To reset the vehicles learning ability, make sure the engine is at operating temperature and operate the vehicle at part throttle, moderate acceleration, and idle conditions, until normal performance returns. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Locations Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions Power Steering Pressure Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3058 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3059 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3060 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3061 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3062 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3063 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3064 Power Steering Pressure Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3065 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3066 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3067 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3068 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3069 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3070 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3071 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3072 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3073 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3074 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3075 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3076 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3077 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3078 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3079 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3080 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3081 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3082 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3083 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3084 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3085 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3086 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3087 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3088 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 3089 Power Steering Pressure Switch Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Page 3090 Power Steering Pressure Switch: Description and Operation This switch informs the PCM when the power steering pressure is high. During high pressure conditions, the Powertrain Control Module (PCM) will increase idle speed to compensate for the additional load. When the switch closes, the PCM will increase idle speed to compensate for the additional load. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 3094 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 3095 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3098 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3099 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3100 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3101 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3102 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3103 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3104 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3105 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3106 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3107 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3108 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3109 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3110 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3111 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3112 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3113 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3114 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3115 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3116 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3117 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3118 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3119 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3120 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3121 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3122 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3123 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3124 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3125 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3126 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3127 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3128 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3129 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 3130 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 3131 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 3136 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 3137 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3140 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3141 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3142 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3143 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3144 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3145 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3146 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3147 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3148 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3149 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3150 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3151 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3152 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3153 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3154 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3155 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3156 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3157 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3158 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3159 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3160 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3161 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3162 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3163 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3164 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3165 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3166 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3167 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3168 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3169 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3170 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 3171 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 3172 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Locations Rear Of Transmission Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions Vehicle Speed Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3178 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3179 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3180 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3181 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3182 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3183 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3184 Vehicle Speed Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3185 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3186 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3187 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3188 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3189 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3190 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3191 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3192 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3193 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3194 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3195 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3196 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3197 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3198 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3199 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3200 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3201 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3202 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3203 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3204 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3205 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3206 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3207 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3208 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description Vehicle Speed Sensor: Description and Operation General Description Vehicle Speed Sensor (2WD) The Vehicle Speed Sensor (VSS) is a pulse counter type input that informs the Powertrain Control Module (PCM) how fast the vehicle is being driven. The VSS system uses an inductive sensor mounted in the tail housing of the transmission and a toothed reluctor wheel on the tail shaft. As the reluctor rotates, the teeth alternately interfere with the magnetic field of the sensor creating an induced voltage pulse. The VSS produces an AC voltage signal that increases with vehicle speed. The PCM processes this signal and sends it to the instrument panel, EVO module, chime module and cruise control module on CKT 817. A malfunction in the VSS system could set Diagnostic Trouble Code (DTC) 24 or DTC 72. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description > Page 3211 Vehicle Speed Sensor: Description and Operation Circuit Operation The Speed Sensor Circuit consists of a magnetic type sensor and wiring. Gear teeth pressed on the Transmission Output Shaft induce an alternating current in the sensor. This sensor generates a sine wave output with a frequency proportional to vehicle speed. The Powertrain Control Module (PCM) converts this signal to an output that is switched to ground at a frequency of 4000 pulses per mile at the DK GRN/WHT wire (CKT 817) which feeds the Turn Signal Alarm, Power Steering Control Module, Instrument Cluster, Cruise Control Module and Radio (Chev only). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Vehicle Speed Sensor: Initial Inspection and Diagnostic Overview PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 3214 Vehicle Speed Sensor: Symptom Related Diagnostic Procedures Chart #1 Speedometer And Cruise Control Inoperative; Code 24 Not Set Symptom Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 3220 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3223 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3224 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3225 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3226 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3227 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3228 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3229 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3230 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3231 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3232 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3233 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3234 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3235 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3236 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3237 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3238 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3239 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3240 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3241 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3242 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3243 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3244 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3245 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3246 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3247 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3248 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3249 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3250 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3251 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3252 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3253 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3254 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 3255 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 3256 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Specifications Oil Pressure Switch (For Fuel Pump): Specifications Fuel Pump Switch and Engine Oil Pressure Sensor ................................................................................................................................... 12 Nm (106 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch > Page 3262 Oil Pressure Switch (For Fuel Pump): Locations Oil Pressure Sensor/Fuel Pump Switch Fuel Pump - Oil Pressure Switch The sensor is threaded into a TEE fitting at the rear of the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions Oil Pressure Switch (For Fuel Pump): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3265 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3266 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3267 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3268 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3269 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3270 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3271 Oil Pressure Switch (For Fuel Pump): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3272 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3273 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3274 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3275 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3276 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3277 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3278 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3279 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3280 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3281 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3282 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3283 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3284 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3285 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3286 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3287 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3288 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3289 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3290 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3291 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3292 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3293 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3294 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3295 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3296 Fuel Pump Switch/Engine Oil Pressure Gage Sensor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 3297 Fuel Pump Relay Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 3298 Oil Pressure Switch (For Fuel Pump): Description and Operation Fuel Pump - Oil Pressure Switch As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 3299 Oil Pressure Switch (For Fuel Pump): Service and Repair Fuel Pump - Oil Pressure Switch REMOVE OR DISCONNECT 1. Disconnect electrical connector. 2. Fuel pump switch and oil pressure sensor. INSTALL OR CONNECT 1. Fuel pump switch and oil pressure sensor. 2. Tighten to 12 Nm (106 lb in.) 3. Electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 3303 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 3304 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3307 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3308 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3309 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3310 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3311 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3312 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3313 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3314 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3315 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3316 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3317 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3318 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3319 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3320 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3321 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3322 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3323 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3324 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3325 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3326 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3327 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3328 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3329 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3330 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3331 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3332 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3333 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3334 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3335 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3336 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3337 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3338 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 3339 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 3340 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3346 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3347 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3348 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3349 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3350 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3351 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3352 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3353 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3354 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3355 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3356 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3357 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3358 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3359 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3360 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3361 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3362 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3363 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3364 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3365 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3366 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3367 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3368 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3369 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3370 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3371 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3372 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3373 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3374 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3375 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3376 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3381 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3382 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3383 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3384 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3385 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3386 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3387 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3388 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3389 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3390 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3391 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3392 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3393 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3394 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3395 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3396 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3397 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3398 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3399 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3400 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3401 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3402 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3403 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3404 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3405 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3406 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3407 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3408 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3409 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3410 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3411 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Locations > Component Locations > Page 3417 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3420 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3421 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3422 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3423 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3424 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3425 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3426 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3427 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3428 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3429 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3430 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3431 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3432 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3433 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3434 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3435 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3436 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3437 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3438 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3439 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3440 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3441 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3442 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3443 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3444 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3445 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3446 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3447 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3448 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3449 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3450 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3451 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 3452 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 3453 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Sensors and Switches - Powertrain Management > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 3454 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Fuel Pressure > Diagnostic Connector - Fuel Pump > Component Information > Locations Diagnostic Connector - Fuel Pump: Locations The fuel pump test connector is located in the engine compartment near the A/C accumulator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations Fuel Pressure Test Port Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations > Page 3463 Fuel Pressure Test Port: Service and Repair Fuel Test Port Valve CLEAN ^ Area around fuel pressure connection with GM X-3OA or equivalent. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery System / Service and Repair. 3. Fuel pressure connection valve assembly. INSTALL OR CONNECT 1. Fuel pressure connection valve assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ Turn ignition switch to the "ON" position for two seconds, then turn to the "OFF" position for ten seconds. Again turn to "ON" position, and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air/Fuel Mixture > System Information > Specifications Air/Fuel Mixture: Specifications The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air/Fuel Mixture > System Information > Specifications > Page 3467 Air/Fuel Mixture: Adjustments The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Idle Speed > System Information > Specifications Idle Speed: Specifications The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Idle Speed > System Information > Specifications > Page 3471 Idle Speed: Adjustments The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Cleaner Fresh Air Duct/Hose > Component Information > Locations Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: Customer Interest Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 3484 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: All Technical Service Bulletins Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 3490 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 3491 Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 3492 Air Filter Element: Service and Repair Air Ducting Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 3493 REMOVE OR DISCONNECT 1. Loosen wing nuts at front of air cleaner housing. 2. Lift air cleaner lid, Mass Air Flow (MAF) sensor and resonator as a unit. 3. Remove air filter element. INSTALL OR CONNECT 1. Install air filter element. 2. Move air cleaner lid, MAF sensor and resonator into place. 3. Tighten wing nuts. 4. Check clamps at MAF sensor and tighten if necessary. 5. Check joints between duct, resonators and throttle body for possible air leaks. Repair if necessary. NOTICE: If the Mass Air Flow (MAF) sensor is installed backwards, the system will go rich. An arrow cast into the plastic portion of the sensor indicates proper air flow direction. The arrow must point toward the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Fuel Filter > Fuel Pressure Release > System Information > Service and Repair Fuel Pressure Release: Service and Repair WARNING: - To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing fuel system components. - After relieving the fuel system pressure a small amount of fuel may be released when servicing fuel lines or connections. In order to reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting, to catch any fuel that may leak out. Place the shop towel in an approved container when the disconnect is complete. Fuel Pressure Test Port PROCEDURE: 1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine. 2. Loosen the fuel filler cap to relieve tank pressure. 3. Connect the J 34730-1 fuel pressure gauge to the fuel pressure connection on the fuel rail. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage. 4. Install a bleed hose into an approved container and open the valve slowly to relieve system pressure. Fuel connections are now safe for servicing. 5. Drain any fuel remaining in the gauge into an approved container. NOTE: After repairs are complete, tighten the fuel cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Firing Order > Component Information > Specifications > Ignition Firing Order Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Firing Order > Component Information > Specifications > Ignition Firing Order > Page 3502 Firing Order: Specifications Number 1 Cylinder Location For number 1 cylinder locations, See: Ignition Timing/Number One Cylinder/Locations See: Spark Plug Wire Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Ignition Timing > Number One Cylinder > Component Information > Locations > Number 1 Cylinder Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation Timing Marks and Indicators: Locations Crankshaft Rotation Crankshaft Rotation (Typical Crankshaft Pulley) Crankshaft rotation is clockwise when viewed from in front of the crankshaft pulley as shown in the generic image. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation > Page 3512 Timing Marks and Indicators: Locations Timing Marks The ignition timing is completely controlled by the Powertrain Control Module (PCM). No timing reference marks are provided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications Spark Plug Wire: Specifications Wire Harness Support Bolt / Screw ............................................................................................................................................................ 40 Nm (30 lb ft.) Wire Harness Support Channel Bolt / Screw (Right) ................................................................................................................................ 12 Nm (106 lb in.) Wire Harness Support Channel Bolt/Screw (Left) ..................................................................................................................................... 12 Nm (106 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3516 Spark Plug Wire: Locations Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3517 Spark Plug Harness Routing The spark plug wires run down both sides of the engine block under the exhaust manifolds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3518 Spark Plug Wire: Description and Operation The spark plug wire hamess assemblies use carbon impregnated cord conductors, encased in 8 mm (5 / 16-inch) diameter silicone jackets. The silicone jackets withstand very high temperatures and also provide excellent insulation for the high voltage of the system. Silicone spark plug boots form a tight seal to the spark plugs. The material used to construct spark plug wires is very soft. This wire will withstand more heat and carry a higher voltage, but chaffing and cutting become easier. The spark plug wires must be routed correctly to prevent chafing or cutting. When removing a spark plug wire from a spark plug, twist the boot on the spark plug one-half turn while pulling on the boot. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3519 Spark Plug Wire: Testing and Inspection Inspect spark plug wires visually first for any cuts, burns, or damage. While engine is running, inspect for any arcing to ground or other components. Use a spray bottle to lightly coat the spark plug wires with water while observing idle quality. If idle quality diminishes or engine stalls, spark plug wires should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3520 Spark Plug Wire: Service and Repair Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3521 Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3522 Spark Plug Harness Routing NOTICE: The boots should be twisted one-half turn while removing. Do not pull on the wire harnesses to remove them from the spark plugs. Pull on the boots, or use a tool designed for this purpose. REMOVE OR DISCONNECT Numbers included in this procedure refer to caption numbers in the included images. 1. Left bank spark plug wire boots from spark plugs. 2. Left bank spark plug wire harness support channel bolts / screws (19) and channel. Rear bolt / screw (19) is located behind exhaust manifold takedown. Loosen this bolt / screw using a 10 mm wrench then slide channel upward to disengage from bolt / screw (19). 3. Left bank spark plug wire harness from clip (17) located behind air injection reactor (AIR) pump. 4. Right bank spark plug wire boots from spark plugs. 5. Air intake resonator. With mechanical cooling fan: A. Upper radiator fan shroud, B. Loosen fan pulley nuts. C. Fan belt. D. Mechanical fan and pulley. E. Mechanical fan pulley bracket nuts and bracket. F. Radiator outlet pipe nuts from A/C compressor mounting studs. 6. Serpentine drive belt. 7. Raise and suitably support vehicle. 8. Transmission oil cooler line support bolt / screw from accessory drive bracket. 9. Serpentine drive belt tensioner bolts/screws and tensioner. 10. A/C compressor attaching bolts/screws Reposition A/C compressor to provide access to front wire harness support (27). 11. Right wire harness support bolt / screw (28). 12. Right wire harness from support (27). 13. Left and right bank spark plug wire harnesses (6) from distributor. 14. Left wire harness from clips (17, 20, 21 and 23). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 3523 ^ Insert screwdriver into tab on top of clip to disengage. 15. Right wire harness from clips (16, 17, and 21). ^ Insert screwdriver into tab on top of clip to disengage. NOTICE: When replacing spark plug wire harnesses (secondary wiring), route the wire harnesses correctly and through the proper retainers. Failure to route the wire harnesses properly can lead to radio ignition noise and cross-firing of the spark plugs, or shorting of the leads to ground. INSTALL OR CONNECT 1. Right wire harness to clips (16, 17 and 21). 2. Left wire harness to clips (17, 20, 21 and 23). 3. Right wire harness to support (27). 4. Right wire harness support bolt / screw (28). Tighten ^ Bolt / screw (28) to 40 Nm (30 lb ft.). 5. A/C compressor to bracket. 6. A/C compressor attaching bolts / screws and rear bracket nut. Tighten A. A/C compressor bolts / screws to 50 Nm (37 lb ft.). B. A/C compressor rear bracket nut to 41 Nm (30 lb ft.). 7. Serpentine drive belt tensioner and tensioner bolts / screws. Tighten ^ Tensioner bolts / screws to 25 Nm (18 lb ft.). 8. Transmission oil cooler line support bolt / screw. Tighten ^ Oil cooler line support bolt / screw to 1.9 Nm (17 lb in.). 9. Lower vehicle. 10. Serpentine drive belt. With mechanical cooling fan: A. Radiator outlet pipe nuts from A/C compressor mounting studs. Tighten ^ Radiator outlet pipe nuts to 16 Nm (12 lb ft.). B. Mechanical fan pulley bracket nuts and bracket. Tighten ^ Mechanical fan pulley bracket nuts to 50 Nm (37 lb .ft). C. Mechanical fan pulley, fan and nuts. ^ Finger tighten only. D. Fan belt. Tighten ^ Mechanical fan nuts to 26 Nm (19 lb ft.). E. Upper radiator fan shroud. 11. Air intake resonator. 12. Right bank spark plug wire boots to spark plugs. 13. Left bank spark plug wire harness to clip (17) located behind AIR pump. 14. Left bank spark plug wire harness support channel and bolts/screws (19). Rear bolt / screw (19) is located behind exhaust manifold takedown. Slide channel onto bolt / screw (19) then tighten using a 10 mm wrench. 15. Left bank spark plug wire harness boots to spark plugs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Specifications Distributor Cap: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement Distributor Cap: Service and Repair Replacement Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Distributor cap (30). 2. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 3. Vacuum harness assembly to distributor assembly. 4. Connect four-terminal PCM connector to distributor. 5. Spark plug wire harness assemblies to distributor assembly. 6. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement > Page 3530 Distributor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications Ignition Rotor: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Distributor Rotor Bolt / Screw .............................................................................................................. ....................................................... 0.7 Nm (6 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 3534 Ignition Rotor: Service and Repair Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). 7. Rotor bolts / screws (32) using J 39998 or equivalent. 8. Rotor assembly (32). 9. Distributor cover (33) and shield (34). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Shield (34) and distributor cover (33). 2. Rotor (32). 3. Rotor bolts / screws (31) using J 39998 or equivalent. Tighten ^ Rotor bolts / screws (31) to 0.7 Nm (61 lb in.). 4. Distributor cap (30). 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 3535 ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 6. Vacuum harness assembly to distributor assembly. 7. Connect four-terminal PCM connector to distributor. 8. Spark plug wire harness assemblies to distributor assembly. 9. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications Spark Plug: Specifications Spark Plug Install Torque .................................................................................................................... ........................................................ 27 Nm (20 lb ft.) Spark Plug Gap ................................................................................................................................... ........................................................ 1.27 mm (0.050") Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 3539 Spark Plug Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 3540 Spark Plug: Service Precautions It is important that technicians wash their hands after handling coated spark plugs and before smoking. The coating itself is a nonhazardous material and incidental contact will not cause any adverse affects. However, exposure to polymer vapors (the result of a cigarette being coated from handling, then burned) may cause flu like symptoms and should be avoided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 3541 Spark Plug ID Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 3542 Spark Plug: Description and Operation Platinum-tipped, resistor-type, tapered-seat spark plugs are used on the engine assembly. No gasket is used on these tapered-seat spark plugs. When replacing spark plugs, use only the type specified. Normal service is assumed to be a mixture of idling, slow speed, and high speed driving. Occasional or intermittent high-speed driving is needed for good spark plug performance. It gives increased combustion heat, burning away carbon or oxides that have built up from frequent idling, or continual stop-and-go driving. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 3543 Spark Plug: Testing and Inspection WORN OR DIRTY Worn or dirty spark plugs may give satisfactory operation at idling speed, but frequently fail at higher rpm. Faulty spark plugs may cause poor fuel economy, power loss, loss of speed, hard starting and generally poor engine performance. Follow the scheduled maintenance service recommendations to assure satisfactory spark plug performance. NORMAL Normal spark plug operation will result in brown to grayish - tan deposits appearing on the portion of the spark plug that projects into the cylinder area. A small amount of red - brown, yellow, and white powdery material may also be present on the insulator tip around the center electrode. These deposits are normal combustion by-products of fuels and lubricating oils with additives. MISFIRING Engine assemblies which are not running properly are often referred to as "misfiring." This means the ignition spark is not igniting the fuel/air mixture at the proper time, While other ignition and fuel system causes must also be considered, possible causes include ignition system conditions which allow the spark voltage to reach ground in some other manner than by jumping across the air gap at the tip of the spark plug, leaving the fuel/air mixture unburned. Misfiring may also occur when the tip of the spark plug becomes overheated and ignites the mixture before the spark jumps. This is referred to as "pre-ignition." CARBON FOULING Carbon fouling of the spark plug is indicated by dry, black carbon (soot) deposits on the portion of the spark plug in the cylinder. Excessive idling and slow speeds under light engine loads can keep the spark plug temperatures so low that these deposits are not burned off. Over - rich fuel mixtures or poor ignition system output may also be the cause. OIL FOULING Oil fouling of the spark plug is indicated by wet oily deposits on the portion of the spark plug in the cylinder. This may be caused by oil getting past worn piston rings. This condition also may occur during break-in of new or newly overhauled engine assemblies. DEPOSITS Deposit fouling of the spark plug occurs when the normal red - brown, yellow or white deposits of combustion by - products become sufficient to cause misfiring. In some cases, these deposits may melt and form a shiny glaze on the insulator around the center electrode. If the fouling is found in only one or two cylinders, valve stem clearances or intake valve seals may be allowing excess lubricating oil to enter the cylinder, particularly if the deposits are heavier on the side of the spark plug that was facing the intake valve. CRACKED OR BROKEN Cracked or broken insulators may be the result of improper installation or heat shock to the insulator material. Upper insulators can be broken when a poorly fitting tool is used during installation or removal, or when the park plug is hit from the outside. Cracks in the upper insulator may be inside the shell and not visible. Also, the breakage may not cause problems until oil or moisture penetrates the crack later. A broken or cracked lower insulator tip (around the center electrode) may result from "heat shock" (spark plug suddenly operating too hot). "Heat shock" breakage in the lower insulator tip generally occurs during severe engine operating conditions (high speeds or heavy loading) and may be caused by over - advanced timing or low grade fuels. Heat shock refers to a rapid increase in the tip temperature that causes the insulator material to crack. Damage during gapping can happen if the gapping tool is pushed against the center electrode or the insulator around it, causing the insulator to crack. When gapping a spark plug, make the adjustment by only bending the ground side terminal, keeping the tool clear of other parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Spark Plug > Component Information > Specifications > Page 3544 Spark Plug: Service and Repair Spark Plug Assembly REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Spark plug wire harness assemblies from spark plugs. Refer to "Spark Plug Wire Harness Assembly Replacement" in this section. ^ Note positions of wires before removing. NOTICE: Clean dirt and debris from spark plug recess areas. 3. Spark plugs from cylinder head assemblies. NOTICE: Be sure spark plugs thread smoothly into cylinder head assemblies and are fully seated. Cross threading or failing to fully seat spark plugs can cause overheating of spark plugs, exhaust blow-by, or thread damage. Follow recommended torque specifications carefully. Over or under - tightening can also cause severe damage to cylinder head assemblies or spark plug. Check spark plug gap using a wire type gauge before installing. If spark plug gaps are not adjusted correctly, engine idle quality may be seriously affected. A wire type gauge must be used (as opposed to a flat feeler type gauge) to insure an accurate reading. INSTALL OR CONNECT 1. Spark plugs to cylinder head assemblies. Tighten ^ Spark plugs to 27 Nm (20 lb ft.). 2. Spark plug wire harness assemblies, routed properly as note during removal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Compression Check > System Information > Specifications Compression Check: Specifications The lowest reading cylinder should not be less than 70% of the highest and no cylinder reading should be less than 689 kPa (100 psi). Perform compression test with engine at normal operating temperature, spark plugs removed and throttle wide open. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Valve Clearance > System Information > Specifications Valve Clearance: Specifications VALVE LASH Turn rocker arm stud nut until all lash is eliminated (zero lash), then tighten nut additional turn in 1/4 turn increments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Tune-up and Engine Performance Checks > Valve Clearance > System Information > Specifications > Page 3551 Valve Clearance: Adjustments Fig. 5 Valve Lash Adjustment Adjust valves, Fig.5, with engine at normal operating temperature. Rotate engine until No. 1 cylinder is in position to fire. Adjust exhaust valves 1-3-4-8 and intake valves 1-2-5-7. Crank engine one complete revolution, then adjust exhaust valves 2-5-6-7 and intake vales 3-4-6-8. On all engines, the following procedure, performed with the engine running, should only be performed if readjustment is required. 1. After engine has been warmed up to normal operating temperature, remove valve cover and install a new valve cover gasket. 2. With engine running at idle speed, back off valve rocker arm nut until rocker arm starts to clatter. 3. Turn rocker arm nut down slowly until clatter just stops. This is the zero lash position. 4. Turn nut down 1/4 additional turn and pause 10 seconds until engine runs smoothly. Repeat additional 1/4 turns, pausing 10 seconds each time, until nut has been turned down the number of turns listed in "Valve Clearance Specifications chart from the zero lash position. This preload adjustment must be done slowly to allow lifter to adjust itself to prevent the possibility of interference between valve head and top of piston, which might result in internal damage and/or bent push rods. Noisy lifters should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > A/C Signal > Component Information > Locations A/C Signal: Locations Relay Location The A/C clutch relay is located in the underhood electrical center. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > A/C Signal > Component Information > Description and Operation > A/C Refrigerant Pressure Signal A/C Signal: Description and Operation A/C Refrigerant Pressure Signal This signal is used by the Powertrain Control Module (PCM) to enable cooling fans when compressor head pressure reaches about 89 psi. If a fault is present in the A/C refrigerant pressure sensor circuit, a Diagnostic Trouble Code (DTC) 66 and 67 will set, and the A/C clutch would be disabled. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > A/C Signal > Component Information > Description and Operation > A/C Refrigerant Pressure Signal > Page 3558 A/C Signal: Description and Operation A/C Request Signal When the heater and A/C control is placed in the A/C Mode, a request signal is sent to the PCM. The PCM will then energize the A/C clutch relay, unless abnormally high or low A/C pressure is detected by the A/C refrigerant pressure sensor. The PCM will also turn the cooling fans "ON" when A/C is requested. The A/C clutch relay is controlled by the PCM so that the PCM can increase idle speed before turning "ON" the clutch or disable the clutch during WOT, and high coolant temperature. This system consists of a heater and A/C control, A/C pressure cycling switch, an A/C refrigerant pressure sensor, an A/C clutch relay, the compressor clutch, and the PCM. The A/C refrigerant pressure cycling switch is closed when there is sufficient system pressure (depending on refrigerant charge (R134a) and ambient temperature). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > A/C Signal > Component Information > Description and Operation > Page 3559 A/C Signal: Testing and Inspection The Powertrain Control Module (PCM) will energize the A/C clutch whenever the engine is running less than 3800 RPM and A/C has been requested unless any of the following conditions are met: ^ Wide Open Throttle (WOT). ^ A/C head pressure greater than 429 psi or less than 0 psi (as determined by the A/C refrigerant pressure sensor), ^ Low ignition voltage. ^ Engine speed greater than 5250 RPM for 30 seconds. ^ Engine Coolant Temperature (ECT) greater than 124°C (255°F). Chart C-10 should be used for diagnosing the electrical portion of the A/C circuit. Refer to Heating and Air Conditioning for diagnosing the refrigerant portion of the system. The Tech 1 will be used in diagnosing the system, as it has the ability to display the A/C request input to the PCM, A/C compressor status, A/C system pressure, as well as displaying when the PCM has commanded the A/C clutch "ON." Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 3564 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3567 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3568 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3569 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3570 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3571 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3572 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3573 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3574 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3575 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3576 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3577 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3578 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3579 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3580 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3581 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3582 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3583 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3584 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3585 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3586 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3587 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3588 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3589 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3590 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3591 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3592 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3593 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3594 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3595 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3596 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3597 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3598 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 3599 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 3600 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Specifications Intake Air Temperature Sensor: Specifications Torque Valve Torque Valve Induction Air Sensor 44 in.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor Intake Air Temperature Sensor: Locations IAT Sensor The Intake Air Temperature (IAT) sensor is located in the air ducting, just forward of the throttle body assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 3606 Intake Air Temperature Sensor: Locations Intake Air Temperature (IAT) Sensor Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 3607 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions Intake Air Temperature Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3610 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3611 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3612 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3613 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3614 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3615 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3616 Intake Air Temperature Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3617 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3618 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3619 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3620 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3621 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3622 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3623 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3624 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3625 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3626 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3627 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3628 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3629 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3630 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3631 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3632 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3633 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3634 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3635 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3636 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3637 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3638 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3639 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3640 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3641 Intake Air Temperature (IAT) Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 3642 Intake Air Temperature Sensor: Description and Operation Engine Coolant Temperature (ECT) Sensor The Intake Air Temperature (IAT) sensor is a thermistor (a resistor which changes value based on temperature). It is mounted in the air intake duct. Low temperature produces a high resistance and high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the sensor through a resistor in the PCM and measures the voltage. The voltage will be high when the intake air is cold, and low when the intake manifold air is hot. By measuring the voltage, the PCM knows the intake air temperature. A failure in the IAT sensor circuit should set either a DTC 23 or DTC 25. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 3643 Intake Air Temperature Sensor: Service and Repair REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Electrical connector. 3. Carefully remove sensor from air duct. INSTALL OR CONNECT 1. Install sensor in engine. 2. Connect electrical connector. 3. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3648 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3649 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3650 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3651 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3652 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3653 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3654 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3655 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3656 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3657 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3658 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3659 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3660 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3661 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3662 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3663 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3664 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3665 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3666 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3667 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3668 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3669 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3670 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3671 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3672 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3673 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3674 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3675 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3676 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3677 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3678 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications Coolant Temperature Sensor/Switch (For Computer): Specifications Engine Coolant Temperature (ECT) Sensor ................................................................................................................................................ 23 Nm (17 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 3682 Coolant Temperature Sensor/Switch (For Computer): Locations Left Front Of Engine The engine coolant temperature sensor is located near water pump. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 3683 Coolant Temperature Sensor/Switch (For Computer): Description and Operation Engine Coolant Temperature Sensor The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) immersed in the engine coolant stream. Low coolant temperature produces a high resistance while high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the ECT through a resistor in the PCM and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage. the PCM knows the engine coolant temperature. Engine coolant temperature affects most systems the PCM controls. A failure in the ECT circuit should set either a Diagnostic Trouble Code (DTC) 14 or 15. Remember these DTCs indicate a failure in the engine coolant temperature sensor circuit, so proper use of the chart will lead to either repairing a wiring problem or replacing the sensor to properly repair a problem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 3684 Coolant Temperature Sensor/Switch (For Computer): Service and Repair Engine Coolant Temperature Sensor IMPORTANT: Care must be taken when handling engine coolant (ECT) temperature sensor. Damage to engine coolant sensor will affect proper operation of the fuel injection system. REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Relieve coolant pressure. 3. Electrical connector. 4. Carefully back out sensor. INSTALL OR CONNECT 1. Coat threads with sealer. 2. Install sensor in engine. 3. Torque to 23 Nm (17 ft lb). 4. Connect electrical connector. 5. Refill lost coolant. 6. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3689 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3690 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3691 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3692 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3693 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3694 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3695 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3696 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3697 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3698 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3699 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3700 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3701 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3702 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3703 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3704 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3705 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3706 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3707 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3708 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3709 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3710 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3711 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3712 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3713 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3714 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3715 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3716 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3717 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3718 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3719 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Locations > Component Locations Data Link Connector: Component Locations The Data Link Connector (DLC) is located under the dashboard in the center of the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Locations > Component Locations > Page 3724 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions Data Link Connector: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3727 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3728 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3729 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3730 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3731 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3732 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3733 Data Link Connector: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3734 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3735 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3736 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3737 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3738 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3739 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3740 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3741 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3742 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3743 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3744 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3745 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3746 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3747 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3748 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3749 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3750 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3751 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3752 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3753 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3754 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3755 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3756 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3757 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3758 Data Link Connector: Connector Views Data Link Connector (DLC) DLC Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Diagrams > Diagram Information and Instructions > Page 3759 Data Link Connector (DLC): Pin Assignment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Description and Operation > Circuit Operation Data Link Connector: Description and Operation Circuit Operation The Data Stream (on the 800 CKT) uses a 8192 Baud Rate During normal vehicle operation the Powertrain Control Module (PCM) serves as the "Master" Module. When using the Tech-1 the Tech-1, will serve as the "Master" Module and interrogate any Module on the 800 CKT. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Data Link Connector > Component Information > Description and Operation > Circuit Operation > Page 3762 Data Link Connector: Description and Operation General Description DLC DATA LINK CONNECTOR (DLC) The provision for communicating from vehicle to scanner is the DLC. It is usually located under the instrument panel and is sometimes covered by a plastic cover labeled "DIAGNOSTIC CONNECTOR." It is used in the assembly plant to receive information in checking that the engine is operating properly before it leaves the plant. The connector can also be used by the service technician to identify Powertrain Control Module ( PCM) stored trouble codes. NOTE: There are two different types of DLC connectors, a 12 terminal and a 16 terminal. ONLY the 12 terminal connector which is equipped with a terminal "B" will flash DTC codes through the "Service Engine Soon" / Malfunction Indicator Lamp (MIL). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage Engine Control Module: Technical Service Bulletins Engine Controls - Aftermarket Accessory Usage INFORMATION Bulletin No.: 04-06-04-054B Date: November 18, 2010 Subject: Info - Non-GM Parts and Accessories (Aftermarket) Models: 2011 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add model years and update to the new U.S. Fixed Operation Manager (FOM) and Canada Warranty Manager (WM) names. Please discard Corporate Bulletin Number 04-06-04-054A (Section 06 - Engine/Propulsion System). The recent rise and expansion of companies selling non-GM parts and accessories has made it necessary to issue this reminder to dealers regarding GM's policy on the use and installation of these aftermarket components. When a dealer is performing a repair under the New Vehicle Limited Warranty, they are required to use only genuine GM or GM-approved parts and accessories. This applies to all warranty repairs, special policy repairs or any repairs paid for by GM. Parts and accessories advertised as being "the same" as parts manufactured by GM, but not sold through GM, do not qualify for use in warranty repairs, special policy repairs or any repairs paid for by GM. During a warranty repair, if a GM original equipment part is not available through GM Customer Care and Aftersales (GM CC&A;), ACDelco(R) distributors, other GM dealers or approved sources, the dealer is to obtain comparable, non-GM parts and clearly indicate, in detail, on the repair order the circumstances surrounding why non-GM parts were used. The dealer must give customers written notice, prior to the sale or service, that such parts or accessories are not marketed or warranted by General Motors. It should also be noted that dealers modifying new vehicles and installing equipment, parts and accessories obtained from sources not authorized by GM are responsible for complying with the National Traffic and Motor Vehicle Safety Act. Certain non-approved parts or assemblies, installed by the dealer or its agent not authorized by GM, may result in a change to the vehicle's design characteristics and may affect the vehicle's ability to conform to federal law. Dealers must fully understand that non-GM approved parts may not have been validated, tested or certified for use. This puts the dealer at risk for potential liability in the event of a part or vehicle failure. If a GM part failure occurs as the result of the installation or use of a non-GM approved part, the warranty will not be honored. A good example of non-authorized modification of vehicles is the result of an ever increasing supply of aftermarket devices available to the customer, which claim to increase the horsepower and torque of the Duramax(TM) Diesel Engines. These include the addition of, but are not limited to one or more of the following modifications: - Propane injection - Nitrous oxide injection - Additional modules (black boxes) that connect to the vehicle wiring systems - Revised engine calibrations downloaded for the engine control module - Calibration modules which connect to the vehicle diagnostic connector - Modification to the engine turbocharger waste gate Although the installation of these devices, or modification of vehicle components, can increase engine horsepower and torque, they may also negatively affect the engine emissions, reliability and/or durability. In addition, other powertrain components, such as transmissions, universal joints, drive shafts, and front/rear axle components, can be stressed beyond design safety limits by the installation of these devices. General Motors does not support or endorse the use of devices or modifications that, when installed, increase the engine horsepower and torque. It is because of these unknown stresses, and the potential to alter reliability, durability and emissions performance, that GM has adopted a policy that prevents any UNAUTHORIZED dealer warranty claim submissions to any remaining warranty coverage, to the powertrain and driveline components whenever the presence of a non-GM (aftermarket) calibration is confirmed - even if the non-GM control module calibration is subsequently removed. Refer to the latest version of Bulletin 09-06-04-026 (V8 Gas Engines) or 06-06-01-007 (Duramax(TM) Diesel Engines) for more information on dealer requirements for calibration verification. These same policies apply as they relate to the use of non-GM accessories. Damage or failure from the use or installation of a non-GM accessory will not be covered under warranty. Failure resulting from the alteration or modification of the vehicle, including the cutting, welding or disconnecting of the vehicle's original equipment parts and components will void the warranty. Additionally, dealers will NOT be reimbursed or compensated by GM in the event of any legal inquiry at either the local, state or federal level that Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3767 results from the alteration or modification of a vehicle using non-GM approved parts or accessories. Dealers should be especially cautious of accessory companies that claim the installation of their product will not void the factory warranty. Many times these companies have even given direction on how to quickly disassemble the accessory in an attempt to preclude the manufacturer from finding out that is has been installed. Any suspect repairs should be reviewed by the Fixed Operations Manager (FOM), and in Canada by the Warranty Manager (WM) for appropriate repair direction. If it is decided that a goodwill repair is to be made on the vehicle, even with the installation of such non-GM approved components, the customer is to be made aware of General Motors position on this issue and is to sign the appropriate goodwill documentation required by General Motors. It is imperative for dealers to understand that by installing such devices, they are jeopardizing not only the warranty coverage, but also the performance and reliability of the customer's vehicle. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3768 Engine Control Module: Technical Service Bulletins PROM - Reprogram Using Off Board Program Adapter File In Section: 6E - Engine Fuel & Emission Bulletin No.: 73-65-13 Date: March, 1997 INFORMATION Subject: Reprogramming Capability using the Off Board Programming Adapter Models: 1993-97 Passenger Cars and Trucks (Applicable Reprogrammable Vehicles) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3769 The General Motors vehicles contain Electronically Reprogrammable Devices (i.e. PCM, VCM, ECM). These vehicles cannot be programmed through PROM replacement, however service programming capability is available through the Tech 1/1A, Tech 2 and Techline terminals via direct or remote programming. The Environmental Protection Agency (EPA) has requested that all new vehicle manufacturers ensure their dealers/retailers are aware that they are responsible for providing customers access to reprogramming services at a reasonable cost and in a timely manner. Although programming of controllers has become a common service practice at GM dealers/retailers, the EPA has received reports from consumers and the aftermarket repair industry that they were unable to purchase a new (programmed) Electronically Reprogrammable Device (ERD) over-the-counter. As a result, on August 1, 1995, the Federal Government issued a regulation requiring all manufacturers to make available reprogramming to the independent aftermarket by December 1, 1997. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3770 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3771 Today, the Off Board Programming Adapter (OBPA) is used to reprogram ERD's sold over-the-counter. For all practical purposes, the OBPA takes the place of the vehicle when the vehicle is not available. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3772 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3773 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3774 The list of dealerships/retailers currently own the OBPA (see Attachments 1 - 3). These locations are equipped to provide over-the-counter preprogrammed ERD's. The hardware required to perform reprogramming in addition to the OBPA is a Techline terminal, Tech 1/1A and associated cables and adapters. THE TECH 2 SHOULD NOT BE USED WITH THE OBPA AT THIS TIME BECAUSE OF INADEQUATE OBPA GROUNDING. The current OBPA can support reprogramming on all late model General Motor's vehicles except: ^ Premium V-8's ^ 1996 Diesel Truck ^ Cadillac Catera Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 3775 ^ All 1997 programmable vehicles (requires use of the Tech 2) A modification to the OBPA is being offered by Kent-Moore to support these additional vehicles and to allow reprogramming using the Tech 2. The revisions to the OBPA for the Tech 2 is very important as the Tech 2 is the only tool used for service programming for 1997 and future vehicles. To have the modifications performed, contact Kent-Moore at (800) 345-2233. The revisions (part number J 41207 REV-C) are free of charge for GM dealerships/retailers. A dealership/retailer can purchase the OBPA by contacting Kent-Moore (part number J 41207-C). Support on how to use the OBPA is provided by the Techline Customer Support Center (TCSC) at (800) 828-6860 (English) or (800) 503-3222 (French). If you need to purchase an OBPA and/or cable, contact Kent-Moore at (800) 345-2233. The OBPA retails for $695.00 (includes all revisions 1-4) under part number J 41207-C. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Page 3776 Engine Control Module: Specifications Powertrain Control Module (PCM) .............................................................................................................................................................. 3 Nm (26 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations PCM Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 3779 Engine Control Module: Connector Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 3780 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 3781 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 3782 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions Engine Control Module: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3785 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3786 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3787 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3788 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3789 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3790 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3791 Engine Control Module: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3792 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3793 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3794 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3795 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3796 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3797 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3798 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3799 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3800 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3801 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3802 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3803 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3804 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3805 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3806 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3807 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3808 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3809 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3810 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3811 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3812 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3813 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3814 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3815 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3816 Engine Control Module: Connector Views Powertrain Control Module (PCM): A Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3817 Powertrain Control Module (PCM): B Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3818 Powertrain Control Module (PCM): C Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3819 Powertrain Control Module (PCM): D Pinout Information PCM Connectors CAUTION: Do not backprobe Powertrain Control Module (PCM) connectors! The connectors are sealed for operation in an underhood environment. Backprobing may damage the seal which could eventually cause the connector to fail due to corrosion. This information applies to the PCM connector charts in the next four images. These charts may be used with the J 39700-A breakout box in conjunction with J 39700-110 and J 39700-140 cables and high impedance digital multimeter J 39200 to obtain voltage present for each circuit listed. Install the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3820 breakout box between the PCM connectors and the PCM. The breakout box PIN numbers correspond with the PCM connector PIN numbers. Voltage may vary slightly, but should be very close. Certain exceptions are called out in the chart legend below. The following conditions must be met before checking typical voltages: Key "ON": ^ DVM negative (black) lead connected to a known good ground. ^ Scan tool "NOT" installed. ^ All accessories "OFF." ^ Battery fully charged. Engine Running: ^ All conditions listed above. ^ Engine at normal operating temperature. ^ Engine at idle/closed throttle/operating in "Closed Loop." ^ In park or neutral. CHART LEGEND (1) Less than .5 volt when system enabled. (2) Battery voltage for first two seconds with ignition "ON." (3) Varies. (4) Varies with temperature. (5) Battery voltage when in gear. (6) Less than .5 volt with brake pedal applied. (7) Battery voltage with A/C "ON." (8) Varies with altitude. (9) Less than .5 volt with high power steering load. (*) Less than .5 volt. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3821 Connector "A" RED Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3822 Connector "B" BLACK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3823 Connector "C" GREY/CLEAR Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 3824 Connector "D" BLUE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Page 3825 Engine Control Module: Description and Operation PCM Connectors The Powertrain Control Module (PCM) is the control center of the fuel injection system. It constantly looks at the information from various sensors and controls the systems that affect vehicle performance. The PCM also performs a diagnostic function check of the system. It can recognize operational problems and alert the driver through the Malfunction Indicator Lamp (MIL) "Service Engine Soon" and store Diagnostic Trouble Code(s) (DTC) which identify the problem areas to aid the technicians making repairs. The PCM supplies 5 or 12 volts to power various sensors or switches. This is done through resistances in the PCM which are so high in value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading because its resistance is too low. Therefore, the use of a 10 megohm input impedance digital voltmeter (J 39200) is required to assure accurate voltage readings. Refer to Computers and Controls / System Diagnosis / Flow of Diagnosis / "Strategy Based Diagnostics" for more information on using the diagnostic function of the PCM. MEMORY There are three types of memory storage within the PCM: Read Only Memory (ROM), Random Access Memory (RAM) and Electrically Erasable Programmable Read Only Memory (EEPROM). ROM Read Only Memory (ROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The ROM contains the overall control programs. Once the ROM is programmed, it cannot be changed. The ROM memory is non-erasable, and does not need power to be retained. RAM Random Access Memory (RAM) is the microprocessor "scratch pad." The processor can write into, or read from this memory as needed. This memory is erasable and needs a constant supply of voltage to be retained. If the voltage is lost, the memory is lost. EEPROM Electrically Erasable Programmable Read Only Memory (EEPROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The EEPROM contains the overall control algorithms. The EEPROM can be reprogrammed by using the Tech 1 scan tool or other Decline terminal/equipment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Component Tests and General Diagnostics Engine Control Module: Component Tests and General Diagnostics To display diagnostic trouble codes, use a Tech 1 (or equivalent scanner). Grounding the DLC will NOT flash Diagnostic Trouble Code(s) (DTC), but will enable most outputs when the ignition is "ON" engine "OFF." Grounding the Data Link Connector (DLC) while the engine is running will cause the Malfunction Indicator Lamp (MIL) to flash to indicate "Open" or "Closed Loop. This is referred to as Field Service Mode." To clear the DTCs from memory use the Tech 1 or: ^ ignition "OFF." ^ Disconnect the # 2 fuse (located in the underhood electrical center) for 30 seconds. Since the Powertrain Control Module (PCM) can have a failure which may affect only one circuit, following the diagnostic procedures in this section will determine which circuit has a problem and where it is. If a diagnostic chart indicates that the PCM connections or PCM is the cause of a problem and the PCM is replaced the Knock Sensor (KS) module must be transferred to the new PCM and the new PCM must then be programmed. If this does not correct the problem, one of the following may be the reason: ^ There is a problem with the PCM terminal connections. The diagnostic chart will say PCM connections or PCM. The terminals may have to be removed from the connector in order to check them properly. ^ The problem is intermittent. This means that the problem is not present at the time the system is being checked. In this case. Refer to Diagnosis by Symptom and make a careful physical inspection of all portions of the system involved. ^ Shorted solenoid, relay coil, or harness. Solenoids and relays are turned "ON" and "OFF" by the PCM using internal electronic switches called "drivers." A shorted solenoid, relay coil, or PCM harness will not damage the PCM but will cause the component to be inoperative. J 34636 or BT-8405 testers or equivalent provide a fast accurate means of checking for a shorted coil or a short to battery voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 3828 Engine Control Module: Service and Repair Removal Hardware Removal NOTE: To prevent internal Powertrain Control Module (PCM) damage, the ignition must be "OFF", when disconnecting or reconnecting power to the PCM. Remove or Disconnect: 1. Disconnect negative battery cable 2. Disconnect PCM mounting hardware 3. Disconnect PCM electrical connectors 4. Remove PCM from engine compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 3829 PCM With Knock Sensor Module 5. Remove PCM access cover Removing Knock Sensor Module From PCM 6. Remove knock sensor module from PCM Install or Connect: 1. Install knock sensor module and access cover 2. Install PCM in vehicle 3. Connect PCM electrical connectors 4. Connect PCM mounting hardware 5. Connect negative battery cable EEPROM Programming CAUTION:The software/calibration used for PCM reprogramming must match the vehicle application, or improper operation and/or damage may occur. ^ Ensure battery is charged ^ Turn ignition "ON" ^ Ensure connections to the Data Link Connector (DLC) and battery/cigar lighter are secure ^ Follow the most current Decline terminal/equipment instructions Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 3830 PCM Reprogramming Failure ^ Check PCM connections ^ Check Decline terminal/equipment for latest software version ^ Repeat reprogramming procedures. If it fails again, replace the PCM. The replacement PCM must be programmed. PCM Functional Check ^ Refer to System Diagnosis / Diagnostic System Check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Specifications Idle Air Control (IAC): Specifications Idle Air Control (IAC) Valve Screws ............................................................................................................................................................ 3 Nm (27 lb in.) IAC Valve/Coolant Cover Assembly Screws ............................................................................................................................................. 3.2 Nm (28 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Specifications > Page 3834 Idle Air Control (IAC): Locations Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Specifications > Page 3835 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions Idle Air Control (IAC): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3838 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3839 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3840 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3841 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3842 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3843 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3844 Idle Air Control (IAC): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3845 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3846 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3847 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3848 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3849 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3850 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3851 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3852 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3853 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3854 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3855 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3856 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3857 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3858 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3859 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3860 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3861 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3862 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3863 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3864 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3865 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3866 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3867 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3868 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3869 Idle Air Control (IAC) Valve Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 3870 Idle Air Control (IAC) Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Page 3871 Idle Air Control (IAC): Description and Operation Throttle Body IAC Valve Flow The purpose of the Idle Air Control (IAC) valve assembly is to control engine idle speed while preventing stalls do to changes in engine load. The IAC valve, mounted in the throttle body, controls a portion of the bypass air. An orifice located between the throttle valves also supplies a constant amount of bypass air. By moving a conical valve known as a pintle, IN, towards the seat (to decrease air flow) or OUT, away from the seat (to increase air flow) a controlled amount of air can be bypassed. If engine speed is too low, more air is bypassed to increase RPM. If engine speed is too high, less air is bypassed to decrease RPM. The Powertrain Control Module (PCM) moves the IAC valve in small steps, called counts. These can be measured and displayed by a scan tool which plugs into the Data Link Connector (DLC). During idle, the proper position of the IAC valve is calculated by the PCM, based on battery voltage, coolant temperature, engine load, and engine RPM. If the RPM drops below specification and the throttle valve is closed, the PCM senses a near stall condition and calculates a new valve position to prevent stalling. ^ Engine idle speed is a function of total air flow into the engine based on IAC valve pintle position + crankcase ventilation valve flow + throttle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Page 3872 valve opening + bypass orifice air flow + calibrated vacuum loss through accessories. ^ Controlled idle speed is programmed into the PCM, which determines the correct lAC valve pintle position to maintain the desired idle speed for all engine operating conditions and loads. ^ The minimum idle air rate is set at the factory with a stop screw. This setting allows enough air flow by the throttle valves to cause the IAC valve pintle to be positioned a calibrated number of steps (counts), from the seat, during controlled idle operation. ^ If the IAC valve is disconnected and reconnected with the engine running, the idle speed may be wrong. If this occurs, reset the IAC valve by depressing the accelerator pedal slightly, start and run engine for five seconds, then turn ignition "OFF" for ten seconds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Page 3873 Idle Air Control (IAC): Adjustments To reset Idle Air Control (IAC) valve. 1. Depress accelerator pedal slightly. 2. Start and run engine for 5 seconds. 3. Turn ignition "OFF" for 10 seconds. 4. Restart engine and check for proper idle operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure Idle Air Control (IAC): Service and Repair Idle Air Control (IAC) Reset Procedure 1. Depress the accelerator pedal slightly. 2. Start and run the engine for five seconds. 3. Turn the ignition "OFF" for ten seconds. 4. Restart the engine and check for proper idle operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 3876 Idle Air Control (IAC): Service and Repair Idle Air Control (IAC) Valve Replacement Throttle Body Exploded View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 3877 IAC Valve REMOVE OR DISCONNECT 1. Resonator. 2. Distributor ventilation vacuum line at air intake duct. 3. Electrical connector from Intake Air Temperature (IAT) sensor. 4. Air intake duct. 5. Electrical connector from Idle Air Control (IAC) valve. 6. IAC valve assembly attaching screws. 7. IAC valve assembly. CLEAN AND INSPECT ^ Clean IAC valve O-ring sealing surface, pintle valve seat and air passage. The IAC valve may be cleaned using GM cleaner 1052626 or GM X-66A. Use a shop towel or parts brush to remove heavy deposits. - Shiny spots on the pintle or seat are normal, and do not indicate misalignment or a bent pintle shaft. If air passage has heavy deposits, remove throttle body for complete cleaning. ^ Inspect IAC valve O-ring for cuts, cracks, or distortion. Replace if damaged. NOTICE: If installing a new IAC valve, be sure to replace with an identical part. IAC valve pintle shape and diameter are designed for specific application. MEASURE (IF INSTALLING A NEW IAC) ^ Distance between tip of IAC valve pintle and mounting surface. If greater than 28 mm (1.100 in), use finger pressure to slowly retract the pintle. The force required to retract the pintle of a NEW valve will not cause damage to the valve. INSTALL OR CONNECT 1. Lubricate IAC valve O-ring with clean engine oil. 2. IAC Valve assembly. 3. IAC valve attaching screws. Tighten ^ IAC attaching screws to 3 Nm (27 lb in.). 4. Electrical connector to IAC valve. 5. Air intake duct. 6. Electrical connector to IAT valve. 7. Distributor ventilation vacuum line at air intake duct. 8. Resonator. 9. Reset IAC valve pintle position. A. Depress accelerator slightly. B. Start engine and release accelerator pedal, run engine for 5 seconds. C. Turn engine "OFF" for 10 seconds. D. Restart engine and check for proper idle operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 3878 Idle Air Control (IAC): Service and Repair Idle Air Control/Coolant Cover Assembly Throttle Body Exploded View REMOVE OR DISCONNECT 2. Negative battery cable. 2. Throttle body from intake manifold. ^ Refer to Throttle Body / Service and Repair. DISASSEMBLE 1. Idle Air Control (IAC) valve. 2. IAC valve/coolant cover assembly screws. 3. IAC valve/coolant cover assembly and gasket. ^ Discard gasket Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 3879 CLEAN AND INSPECT 1. Clean gasket sealing surface. 2. Inspect gasket sealing surface for corrosion or damage that would cause a coolant leak. Replace cover assembly or throttle body if necessary. ASSEMBLE 1. Install new gasket and cover assembly. 2. IAC Valve / coolant cover assembly screws. Tighten ^ IAC Valve / coolant cover assembly screws to 3.2 Nm (28 lb in.). 3. If installing a new IAC valve, measure distance between pintle and mounting surface. If greater than 28mm, use finger pressure to slowly retract the pintle. INSTALL OR CONNECT 1. Install and tighten IAC valve attaching screws Tighten ^ IAC Valve assembly screws to 3 Nm (27 lb in.). 2. Install throttle body to intake manifold. 3. Negative battery cable. 4. Reset IAC valve pintle position. Refer to ADJUSTMENTS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Serial Data <--> [Information Bus] > Component Information > Description and Operation Serial Data: Description and Operation The Data Stream (on the 800 CKT) uses a 8192 Baud Rate During normal vehicle operation the Powertrain Control Module (PCM) serves as the "Master" Module. When using the Tech-1 the Tech-1, will serve as the "Master" Module and interrogate any Module on the 800 CKT. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Serial Data <--> [Information Bus] > Component Information > Testing and Inspection > Circuit Operation Serial Data: Testing and Inspection Circuit Operation The Data Stream (on the 800 CKT) uses a 8192 Baud Rate During normal vehicle operation the Powertrain Control Module (PCM) serves as the "Master" Module. When using the Tech-1 the Tech-1, will serve as the "Master" Module and interrogate any Module on the 800 CKT. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Serial Data <--> [Information Bus] > Component Information > Testing and Inspection > Circuit Operation > Page 3885 Serial Data: Testing and Inspection System Diagnostic Charts Serial Data Line Diagnosis (800 CKT) (Part 1 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Serial Data <--> [Information Bus] > Component Information > Testing and Inspection > Circuit Operation > Page 3886 Serial Data Line Diagnosis (800 CKT) (Part 2 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Serial Data <--> [Information Bus] > Component Information > Testing and Inspection > Circuit Operation > Page 3887 Serial Data Line Diagnosis (800 CKT) (Part 1 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Serial Data <--> [Information Bus] > Component Information > Testing and Inspection > Circuit Operation > Page 3888 Serial Data Line Diagnosis (800 CKT) (Part 2 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations > Page 3894 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3897 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3898 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3899 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3900 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3901 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3902 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3903 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3904 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3905 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3906 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3907 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3908 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3909 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3910 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3911 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3912 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3913 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3914 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3915 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3916 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3917 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3918 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3919 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3920 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3921 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3922 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3923 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3924 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3925 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3926 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3927 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3928 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 3929 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 3930 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 3931 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor Module > Component Information > Locations PCM With Knock Sensor Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Knock Sensor Module > Component Information > Locations > Page 3935 Knock Sensor Module: Service and Repair PCM With Knock Sensor Module Removing Knock Sensor Module From PCM REMOVE OR DISCONNECT 1. Negative battery cable. 2. Powertrain Control Module (PCM) from mounting bracket (refer to PCM removal). 3. Knock sensor (KS) module access cover. 4. Knock sensor module. INSTALL OR CONNECT NOTICE: To prevent possible electrostatic discharge damage to the PCM and KS module, Do Not touch the connector pins or soldered components on the circuit board. 1. Knock senor module. 2. Access cover. 3. PCM to mounting bracket (refer to PCM installation). 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions Malfunction Indicator Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3940 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3941 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3942 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3943 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3944 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3945 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3946 Malfunction Indicator Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3947 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3948 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3949 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3950 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3951 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3952 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3953 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3954 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3955 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3956 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3957 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3958 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3959 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3960 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3961 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3962 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3963 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3964 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3965 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3966 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3967 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3968 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3969 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 3970 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications MAP Sensor Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications > Page 3975 Manifold Pressure/Vacuum Sensor: Mechanical Specifications Manifold Absolute Pressure (MAP) Bolt ...................................................................................................................................................... 6 Nm (50 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Page 3976 Manifold Pressure/Vacuum Sensor: Locations MAP Sensor Location Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions Manifold Pressure/Vacuum Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3979 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3980 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3981 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3982 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3983 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3984 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3985 Manifold Pressure/Vacuum Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3986 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3987 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3988 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3989 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3990 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3991 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3992 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3993 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3994 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3995 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3996 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3997 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3998 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 3999 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4000 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4001 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4002 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4003 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4004 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4005 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4006 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4007 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4008 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4009 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4010 Map Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 4011 Manifold Pressure/Vacuum Sensor: Description and Operation MAP Sensor The Manifold Absolute Pressure (MAP) sensor is a pressure sensor that measures changes in intake manifold pressure. The pressure changes as a result of engine load and speed. The MAP sensor converts this to a voltage output. A closed throttle on engine coastdown would produce a relatively low MAP output while a wide-open throttle would produce a high MAP output voltage. This high output voltage is produced because the pressure inside the manifold is the same as outside the manifold, so you measure 100% of outside air pressure. Manifold Absolute Pressure (MAP) is inversely proportional to what you would measure on a vacuum gage. When manifold pressure is high vacuum is low. The MAP sensor is also used to measure barometric pressure under certain conditions which allows the Powertrain Control Module (PCM) to automatically adjust for different altitudes. The PCM sends a 5 volt reference signal to the MAP sensor. As the manifold pressure changes the electrical resistance of the MAP sensor also changes. By monitoring the sensor output voltage the PCM knows the manifold pressure. The PCM uses the MAP sensor to control ignition timing. The MAP sensor is also used for speed density fuel management. When the PCM detects a malfunction with the Mass Air Flow (MAF) sensor circuit the PCM will default to speed density. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 4012 Manifold Pressure/Vacuum Sensor: Service and Repair MAP Sensor Location REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Resonator. 3. Electrical connector. 4. Hold down bolts (2). 5. Sensor from intake manifold. INSTALL OR CONNECT 1. New sensor seal (lightly coated with clean engine oil). 2. Sensor into intake manifold. 3. Hold down bolts. 4. Torque to 6 Nm (50 lb in). 5. Connect electrical connector. 6. Resonator. 7. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Memory Calibration Unit > Component Information > Technical Service Bulletins > PROM/MEMCAL - Identification Marks Memory Calibration Unit: Technical Service Bulletins PROM/MEMCAL - Identification Marks File In Section: 6E - Engine Fuel & Emission Bulletin No.: 44-65-01 Date: October, 1994 Subject: New PROM/MEMCAL Identification Markings Models: 1995 and Prior Passenger Cars and Trucks Note: For the purposes of this document, the terms PROM and MEMCAL will be used interchangeably. To simplify identification of service PROMs. a new external marking format will be implemented. Parts manufactured after Sept. 1994 will feature these new markings. This change will place the full 8-digit service part number on the PROM, in place of the old 4-digit "EXTERNAL ID" number. In the past, parts and service personnel could not identify a PROM without using a cross-reference table that matched external IDs and service numbers. In the future, the cross-reference table will not be required for PROMs; parts will be ordered directly from the number appearing on the PROM. However, the label will retain the broadcast code alpha characters to allow continued use of cross-reference charts, if so desired. Old Marking Format: New Marking Format: ^ Ordering the above PROM from the old marking format would require using a cross-reference chart to determine a service part number, based on the BROAD CAST CODE and EXTERNAL ID NUMBERS. ^ To order from the new format, simply combine the 2nd and 3rd lines to form an 8-digit part number that can be directly ordered from SPO (number 16134624 in the above example). As these changes are phased into the parts inventory, it should be noted that dealers will continue to see parts with both formats for some time in the future. This is because: ^ Millions of vehicles have already been built with the old format. ^ SPO has existing stock of MEMCALs and PROMs with the old format. ^ PROMS with 7-digit part numbers (representing less than 10% of current part numbers) will continue to use the old format. The 7-digit part numbers are easily identified because they always begin with "122xxxx". Due to manufacturing processes, more than one 8-digit part number may appear on a MEMCAL. In this event, service personnel should use the label on the exterior cover of the MEMCAL assembly. To avoid confusion, only the service label will include the BROAD CAST CODE, consisting of letter characters (I.E., ARCL). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Memory Calibration Unit > Component Information > Technical Service Bulletins > PROM/MEMCAL - Identification Marks > Page 4017 CHANGES TO MEMCAL/PROM LABELING FORMATS ^ MEMCALs may use either INK-JET or ADHESIVE labels, as shown. ^ PROMs will always use ADHESIVE labels with the same format as shown for MEMCALs. These changes will become effective on parts manufactured after 10/94. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Quad Driver <--> [Output Driver] > Component Information > Locations Quad Driver: Locations Quad/Output drivers are hard wired onto the ECM/PCM/VCM. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Quad Driver <--> [Output Driver] > Component Information > Locations > Page 4021 Quad Driver: Description and Operation Quad/Output Driver Module The Control Module in this vehicle controls most components with electronic switches which complete a ground circuit when turned on. When the switches are arranged in groups of 4, they can independently control up to 4 outputs and are called Quad Drivers. When the switches are arranged in groups of 7, they can independently control up to 7 outputs and are called Output Drivers. Not all outputs are always used. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Quad Driver <--> [Output Driver] > Component Information > Locations > Page 4022 Quad Driver: Testing and Inspection Little or no quad driver testing was supplied by the manufacturer. The engine module decides when to turn each switch of the driver "ON". Even though some models will set codes, in the end, if you want to check the driver itself, you'll need: 1. To use a scantool to command the suspected driver switch to energize (ground) the circuit, while checking with a test light, 2. To operate the vehicle in a way that should cause the suspected portion of the driver to switch "ON". On the up side, since the early 90's, most driver load circuits utilized circuit breakers. This protected most drivers and engine models from burning up when the circuit was overloaded. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Quad Driver <--> [Output Driver] > Component Information > Locations > Page 4023 Quad Driver: Service and Repair Quad/Output drivers are hard wired onto the ECM/PCM/VCM, and can't be serviced separately. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Technical Service Bulletins > Oxygen Sensors - Silica Contamination Oxygen Sensor: Technical Service Bulletins Oxygen Sensors - Silica Contamination Model Year: 1981 Bulletin No: 81-I-37 File In Group: 60 Number: 11 Date: Feb. 81 Subject: Silica Contamination of Oxygen Sensors and Gelation of Oil. Models Affected: All Oxygen sensor performance can deteriorate if certain RTV silicone gasket materials are used. Other RTV's when used with certain oils, may cause gelation of the oil. The degree of performance severity depends on the type of RTV and application of the engine involved. Therefore, when repairing engines where this item is involved, it is important to use either cork composition gaskets or RTV silicone gasket material approved for such use. GMS (General Motors Sealant) or equivalent material can be used. GMS is available through GMPD with the following part numbers: 1052366 3 oz. 1052434 10.14 oz. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications Oxygen Sensor Output Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications > Page 4030 Oxygen Sensor: Mechanical Specifications Heated Oxygen Sensor (HO2S) .......................................................................................................... ......................................................... 41 Nm (30 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH Engine, Left Side Lower Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 4033 Lower Right Side Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 4034 HO2S Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions Oxygen Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4037 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4038 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4039 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4040 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4041 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4042 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4043 Oxygen Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4044 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4045 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4046 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4047 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4048 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4049 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4050 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4051 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4052 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4053 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4054 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4055 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4056 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4057 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4058 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4059 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4060 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4061 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4062 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4063 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4064 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4065 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4066 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4067 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4068 Oxygen Sensor: Electrical Diagrams Heated Oxygen Sensor (HO2S) Sensor Circuit. Right Heated Oxygen Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 4069 Oxygen Sensor: Description and Operation HO2S Cutaway Oxygen Sensor Element The Heated Oxygen Sensor (HO2S) is essentially a small variable battery; it has the ability to produce a low voltage signal that feeds information on engine exhaust oxygen content to the Powertrain Control Module (PCM). The PCM sends a reference signal of 450 mV. The reference signal serves to run the engine when it is in "Open Loop" mode of operation. When the air/fuel ratio is correct the PCM displays 450 mV. When the engine is operating with a rich air/fuel ratio, there is a reduction of free oxygen in the exhaust stream and the oxygen voltage rises above the reference voltage. The HO2S is constructed from a material (zirconia/platinum) that conducts electricity under certain conditions. At operating temperature, 315°C (60o° F), the element becomes a semiconductor. A platinum coating on the outer surface of the element stimulates further combustion of the exhaust gases right Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 4070 at the surface and this helps keep the element up to the desired temperature. The HO2S has an inter cavity which is filled with atmospheric (reference) air. The reference air has approximately 21% oxygen in it. In this electrical circuit this inter cavity is the positive (+) terminal. The outer surface of the element is exposed to the exhaust gas stream. It is the negative (-) or ground terminal. The oxygen concentration differences between the reference air and exhaust gases produce small voltages. A rich exhaust (excessive fuel) has almost no oxygen. When there is a large difference in the amount of oxygen touching the inside and outside surfaces, there is more conduction, and the sensor puts out a voltage signal above 600 mV. With lean exhaust (excessive oxygen) there is about two percent oxygen in the exhaust. This is a smaller difference in oxygen from the outside surfaces which results in less conduction and a voltage signal below 300 mV. The voltages are monitored and used by the PCM to "fine tune" the air/fuel ratio to achieve the ideal mixture desired. When the engine is running lean. the voltage drops below the reference voltage due to excess oxygen in the exhaust stream. The HO2S provides the feedback information for the "Closed Loop" operating mode of the fuel delivery system. The HO2S indicates to the PCM what is happening in the exhaust. It does not cause things to happen. It is a type of gage: Low voltage output = lean mixture = high oxygen content in exhaust; high voltage output = rich mixture = low oxygen content in the exhaust. An open Heated Oxygen Sensor (HO2S) circuit, should set Diagnostic Trouble Code (DTC) 13 or 63. A constant low voltage in the HO2S circuit could set a DTC 44 or 64. A constant high voltage in the circuit should set a DTC 45 or 65. DTCs 44. 45. 64, or 65 could also be set as a result of fuel system problems. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 4071 Oxygen Sensor: Service and Repair HO2S Location CAUTION: The Heated Oxygen Sensor (HO2S) uses a permanently attached pigtail and connector. This pigtail should not be removed from the oxygen sensor. Damage or removal of the pigtail or connector could affect proper operation of the oxygen sensor. ^ Take care when handling the oxygen sensor. The in-line electrical connector and louvered end must be kept free off grease, dirt or other contaminants. Also, avoid using cleaning solvents of any type. Be careful not to subject the sensor to sharp impact. REMOVAL: NOTICE: The HO2S may be difficult to remove when engine temperature is below 48° C (120° F). Excessive force may damage threads in exhaust pipe. 1. Disconnect the negative battery cable. 2. Raise vehicle. 3. Disconnect the oxygen sensor electrical connector. 4. Carefully remove the oxygen sensor. INSTALLATION: NOTICE: A special anti-seize compound is used on the oxygen sensor threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will already have the compound applied to the threads. If a sensor is removed from an engine, and, if for any reason it is to be reinstalled, the threads must have anti-seize compound applied before reinstallation. 1. Coat the threads of the HO2S with anti-seize compound P/N 5613695, or equivalent if necessary. 2. Install the sensor in the engine, and tighten to 41 Nm (30 ft lb). 3. Connect the electrical connector. 4. Lower vehicle. 5. Connect the negative battery cable. NOTICE: The system has a learning ability which allows it to make corrections for minor variations in the fuel system to improve driveability. When the battery is disconnected the computer's memory is cleared and the learning process has to begin all over again. A change may be noticed in the driving performance of the vehicle. To reset the vehicles learning ability, make sure the engine is at operating temperature and operate the vehicle at part throttle, moderate acceleration, and idle conditions, until normal performance returns. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Locations Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions Power Steering Pressure Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4077 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4078 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4079 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4080 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4081 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4082 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4083 Power Steering Pressure Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4084 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4085 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4086 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4087 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4088 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4089 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4090 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4091 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4092 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4093 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4094 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4095 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4096 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4097 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4098 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4099 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4100 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4101 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4102 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4103 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4104 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4105 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4106 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4107 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4108 Power Steering Pressure Switch Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Page 4109 Power Steering Pressure Switch: Description and Operation This switch informs the PCM when the power steering pressure is high. During high pressure conditions, the Powertrain Control Module (PCM) will increase idle speed to compensate for the additional load. When the switch closes, the PCM will increase idle speed to compensate for the additional load. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage Engine Control Module: Technical Service Bulletins Engine Controls - Aftermarket Accessory Usage INFORMATION Bulletin No.: 04-06-04-054B Date: November 18, 2010 Subject: Info - Non-GM Parts and Accessories (Aftermarket) Models: 2011 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add model years and update to the new U.S. Fixed Operation Manager (FOM) and Canada Warranty Manager (WM) names. Please discard Corporate Bulletin Number 04-06-04-054A (Section 06 - Engine/Propulsion System). The recent rise and expansion of companies selling non-GM parts and accessories has made it necessary to issue this reminder to dealers regarding GM's policy on the use and installation of these aftermarket components. When a dealer is performing a repair under the New Vehicle Limited Warranty, they are required to use only genuine GM or GM-approved parts and accessories. This applies to all warranty repairs, special policy repairs or any repairs paid for by GM. Parts and accessories advertised as being "the same" as parts manufactured by GM, but not sold through GM, do not qualify for use in warranty repairs, special policy repairs or any repairs paid for by GM. During a warranty repair, if a GM original equipment part is not available through GM Customer Care and Aftersales (GM CC&A;), ACDelco(R) distributors, other GM dealers or approved sources, the dealer is to obtain comparable, non-GM parts and clearly indicate, in detail, on the repair order the circumstances surrounding why non-GM parts were used. The dealer must give customers written notice, prior to the sale or service, that such parts or accessories are not marketed or warranted by General Motors. It should also be noted that dealers modifying new vehicles and installing equipment, parts and accessories obtained from sources not authorized by GM are responsible for complying with the National Traffic and Motor Vehicle Safety Act. Certain non-approved parts or assemblies, installed by the dealer or its agent not authorized by GM, may result in a change to the vehicle's design characteristics and may affect the vehicle's ability to conform to federal law. Dealers must fully understand that non-GM approved parts may not have been validated, tested or certified for use. This puts the dealer at risk for potential liability in the event of a part or vehicle failure. If a GM part failure occurs as the result of the installation or use of a non-GM approved part, the warranty will not be honored. A good example of non-authorized modification of vehicles is the result of an ever increasing supply of aftermarket devices available to the customer, which claim to increase the horsepower and torque of the Duramax(TM) Diesel Engines. These include the addition of, but are not limited to one or more of the following modifications: - Propane injection - Nitrous oxide injection - Additional modules (black boxes) that connect to the vehicle wiring systems - Revised engine calibrations downloaded for the engine control module - Calibration modules which connect to the vehicle diagnostic connector - Modification to the engine turbocharger waste gate Although the installation of these devices, or modification of vehicle components, can increase engine horsepower and torque, they may also negatively affect the engine emissions, reliability and/or durability. In addition, other powertrain components, such as transmissions, universal joints, drive shafts, and front/rear axle components, can be stressed beyond design safety limits by the installation of these devices. General Motors does not support or endorse the use of devices or modifications that, when installed, increase the engine horsepower and torque. It is because of these unknown stresses, and the potential to alter reliability, durability and emissions performance, that GM has adopted a policy that prevents any UNAUTHORIZED dealer warranty claim submissions to any remaining warranty coverage, to the powertrain and driveline components whenever the presence of a non-GM (aftermarket) calibration is confirmed - even if the non-GM control module calibration is subsequently removed. Refer to the latest version of Bulletin 09-06-04-026 (V8 Gas Engines) or 06-06-01-007 (Duramax(TM) Diesel Engines) for more information on dealer requirements for calibration verification. These same policies apply as they relate to the use of non-GM accessories. Damage or failure from the use or installation of a non-GM accessory will not be covered under warranty. Failure resulting from the alteration or modification of the vehicle, including the cutting, welding or disconnecting of the vehicle's original equipment parts and components will void the warranty. Additionally, dealers will NOT be reimbursed or compensated by GM in the event of any legal inquiry at either the local, state or federal level that Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4115 results from the alteration or modification of a vehicle using non-GM approved parts or accessories. Dealers should be especially cautious of accessory companies that claim the installation of their product will not void the factory warranty. Many times these companies have even given direction on how to quickly disassemble the accessory in an attempt to preclude the manufacturer from finding out that is has been installed. Any suspect repairs should be reviewed by the Fixed Operations Manager (FOM), and in Canada by the Warranty Manager (WM) for appropriate repair direction. If it is decided that a goodwill repair is to be made on the vehicle, even with the installation of such non-GM approved components, the customer is to be made aware of General Motors position on this issue and is to sign the appropriate goodwill documentation required by General Motors. It is imperative for dealers to understand that by installing such devices, they are jeopardizing not only the warranty coverage, but also the performance and reliability of the customer's vehicle. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4116 Engine Control Module: Technical Service Bulletins PROM - Reprogram Using Off Board Program Adapter File In Section: 6E - Engine Fuel & Emission Bulletin No.: 73-65-13 Date: March, 1997 INFORMATION Subject: Reprogramming Capability using the Off Board Programming Adapter Models: 1993-97 Passenger Cars and Trucks (Applicable Reprogrammable Vehicles) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4117 The General Motors vehicles contain Electronically Reprogrammable Devices (i.e. PCM, VCM, ECM). These vehicles cannot be programmed through PROM replacement, however service programming capability is available through the Tech 1/1A, Tech 2 and Techline terminals via direct or remote programming. The Environmental Protection Agency (EPA) has requested that all new vehicle manufacturers ensure their dealers/retailers are aware that they are responsible for providing customers access to reprogramming services at a reasonable cost and in a timely manner. Although programming of controllers has become a common service practice at GM dealers/retailers, the EPA has received reports from consumers and the aftermarket repair industry that they were unable to purchase a new (programmed) Electronically Reprogrammable Device (ERD) over-the-counter. As a result, on August 1, 1995, the Federal Government issued a regulation requiring all manufacturers to make available reprogramming to the independent aftermarket by December 1, 1997. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4118 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4119 Today, the Off Board Programming Adapter (OBPA) is used to reprogram ERD's sold over-the-counter. For all practical purposes, the OBPA takes the place of the vehicle when the vehicle is not available. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4120 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4121 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4122 The list of dealerships/retailers currently own the OBPA (see Attachments 1 - 3). These locations are equipped to provide over-the-counter preprogrammed ERD's. The hardware required to perform reprogramming in addition to the OBPA is a Techline terminal, Tech 1/1A and associated cables and adapters. THE TECH 2 SHOULD NOT BE USED WITH THE OBPA AT THIS TIME BECAUSE OF INADEQUATE OBPA GROUNDING. The current OBPA can support reprogramming on all late model General Motor's vehicles except: ^ Premium V-8's ^ 1996 Diesel Truck ^ Cadillac Catera Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Engine Controls - Aftermarket Accessory Usage > Page 4123 ^ All 1997 programmable vehicles (requires use of the Tech 2) A modification to the OBPA is being offered by Kent-Moore to support these additional vehicles and to allow reprogramming using the Tech 2. The revisions to the OBPA for the Tech 2 is very important as the Tech 2 is the only tool used for service programming for 1997 and future vehicles. To have the modifications performed, contact Kent-Moore at (800) 345-2233. The revisions (part number J 41207 REV-C) are free of charge for GM dealerships/retailers. A dealership/retailer can purchase the OBPA by contacting Kent-Moore (part number J 41207-C). Support on how to use the OBPA is provided by the Techline Customer Support Center (TCSC) at (800) 828-6860 (English) or (800) 503-3222 (French). If you need to purchase an OBPA and/or cable, contact Kent-Moore at (800) 345-2233. The OBPA retails for $695.00 (includes all revisions 1-4) under part number J 41207-C. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Technical Service Bulletins > Page 4124 Engine Control Module: Specifications Powertrain Control Module (PCM) .............................................................................................................................................................. 3 Nm (26 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations PCM Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 4127 Engine Control Module: Connector Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 4128 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 4129 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Locations > Component Locations > Page 4130 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions Engine Control Module: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4133 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4134 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4135 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4136 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4137 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4138 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4139 Engine Control Module: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4140 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4141 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4142 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4143 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4144 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4145 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4146 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4147 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4148 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4149 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4150 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4151 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4152 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4153 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4154 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4155 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4156 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4157 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4158 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4159 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4160 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4161 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4162 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4163 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4164 Engine Control Module: Connector Views Powertrain Control Module (PCM): A Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4165 Powertrain Control Module (PCM): B Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4166 Powertrain Control Module (PCM): C Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4167 Powertrain Control Module (PCM): D Pinout Information PCM Connectors CAUTION: Do not backprobe Powertrain Control Module (PCM) connectors! The connectors are sealed for operation in an underhood environment. Backprobing may damage the seal which could eventually cause the connector to fail due to corrosion. This information applies to the PCM connector charts in the next four images. These charts may be used with the J 39700-A breakout box in conjunction with J 39700-110 and J 39700-140 cables and high impedance digital multimeter J 39200 to obtain voltage present for each circuit listed. Install the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4168 breakout box between the PCM connectors and the PCM. The breakout box PIN numbers correspond with the PCM connector PIN numbers. Voltage may vary slightly, but should be very close. Certain exceptions are called out in the chart legend below. The following conditions must be met before checking typical voltages: Key "ON": ^ DVM negative (black) lead connected to a known good ground. ^ Scan tool "NOT" installed. ^ All accessories "OFF." ^ Battery fully charged. Engine Running: ^ All conditions listed above. ^ Engine at normal operating temperature. ^ Engine at idle/closed throttle/operating in "Closed Loop." ^ In park or neutral. CHART LEGEND (1) Less than .5 volt when system enabled. (2) Battery voltage for first two seconds with ignition "ON." (3) Varies. (4) Varies with temperature. (5) Battery voltage when in gear. (6) Less than .5 volt with brake pedal applied. (7) Battery voltage with A/C "ON." (8) Varies with altitude. (9) Less than .5 volt with high power steering load. (*) Less than .5 volt. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4169 Connector "A" RED Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4170 Connector "B" BLACK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4171 Connector "C" GREY/CLEAR Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Diagram Information and Instructions > Page 4172 Connector "D" BLUE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Diagrams > Page 4173 Engine Control Module: Description and Operation PCM Connectors The Powertrain Control Module (PCM) is the control center of the fuel injection system. It constantly looks at the information from various sensors and controls the systems that affect vehicle performance. The PCM also performs a diagnostic function check of the system. It can recognize operational problems and alert the driver through the Malfunction Indicator Lamp (MIL) "Service Engine Soon" and store Diagnostic Trouble Code(s) (DTC) which identify the problem areas to aid the technicians making repairs. The PCM supplies 5 or 12 volts to power various sensors or switches. This is done through resistances in the PCM which are so high in value that a test light will not light when connected to the circuit. In some cases, even an ordinary shop voltmeter will not give an accurate reading because its resistance is too low. Therefore, the use of a 10 megohm input impedance digital voltmeter (J 39200) is required to assure accurate voltage readings. Refer to Computers and Controls / System Diagnosis / Flow of Diagnosis / "Strategy Based Diagnostics" for more information on using the diagnostic function of the PCM. MEMORY There are three types of memory storage within the PCM: Read Only Memory (ROM), Random Access Memory (RAM) and Electrically Erasable Programmable Read Only Memory (EEPROM). ROM Read Only Memory (ROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The ROM contains the overall control programs. Once the ROM is programmed, it cannot be changed. The ROM memory is non-erasable, and does not need power to be retained. RAM Random Access Memory (RAM) is the microprocessor "scratch pad." The processor can write into, or read from this memory as needed. This memory is erasable and needs a constant supply of voltage to be retained. If the voltage is lost, the memory is lost. EEPROM Electrically Erasable Programmable Read Only Memory (EEPROM) is a permanent memory that is physically soldered to the circuit boards within the PCM. The EEPROM contains the overall control algorithms. The EEPROM can be reprogrammed by using the Tech 1 scan tool or other Decline terminal/equipment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Component Tests and General Diagnostics Engine Control Module: Component Tests and General Diagnostics To display diagnostic trouble codes, use a Tech 1 (or equivalent scanner). Grounding the DLC will NOT flash Diagnostic Trouble Code(s) (DTC), but will enable most outputs when the ignition is "ON" engine "OFF." Grounding the Data Link Connector (DLC) while the engine is running will cause the Malfunction Indicator Lamp (MIL) to flash to indicate "Open" or "Closed Loop. This is referred to as Field Service Mode." To clear the DTCs from memory use the Tech 1 or: ^ ignition "OFF." ^ Disconnect the # 2 fuse (located in the underhood electrical center) for 30 seconds. Since the Powertrain Control Module (PCM) can have a failure which may affect only one circuit, following the diagnostic procedures in this section will determine which circuit has a problem and where it is. If a diagnostic chart indicates that the PCM connections or PCM is the cause of a problem and the PCM is replaced the Knock Sensor (KS) module must be transferred to the new PCM and the new PCM must then be programmed. If this does not correct the problem, one of the following may be the reason: ^ There is a problem with the PCM terminal connections. The diagnostic chart will say PCM connections or PCM. The terminals may have to be removed from the connector in order to check them properly. ^ The problem is intermittent. This means that the problem is not present at the time the system is being checked. In this case. Refer to Diagnosis by Symptom and make a careful physical inspection of all portions of the system involved. ^ Shorted solenoid, relay coil, or harness. Solenoids and relays are turned "ON" and "OFF" by the PCM using internal electronic switches called "drivers." A shorted solenoid, relay coil, or PCM harness will not damage the PCM but will cause the component to be inoperative. J 34636 or BT-8405 testers or equivalent provide a fast accurate means of checking for a shorted coil or a short to battery voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 4176 Engine Control Module: Service and Repair Removal Hardware Removal NOTE: To prevent internal Powertrain Control Module (PCM) damage, the ignition must be "OFF", when disconnecting or reconnecting power to the PCM. Remove or Disconnect: 1. Disconnect negative battery cable 2. Disconnect PCM mounting hardware 3. Disconnect PCM electrical connectors 4. Remove PCM from engine compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 4177 PCM With Knock Sensor Module 5. Remove PCM access cover Removing Knock Sensor Module From PCM 6. Remove knock sensor module from PCM Install or Connect: 1. Install knock sensor module and access cover 2. Install PCM in vehicle 3. Connect PCM electrical connectors 4. Connect PCM mounting hardware 5. Connect negative battery cable EEPROM Programming CAUTION:The software/calibration used for PCM reprogramming must match the vehicle application, or improper operation and/or damage may occur. ^ Ensure battery is charged ^ Turn ignition "ON" ^ Ensure connections to the Data Link Connector (DLC) and battery/cigar lighter are secure ^ Follow the most current Decline terminal/equipment instructions Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Engine Control Module > Component Information > Testing and Inspection > Page 4178 PCM Reprogramming Failure ^ Check PCM connections ^ Check Decline terminal/equipment for latest software version ^ Repeat reprogramming procedures. If it fails again, replace the PCM. The replacement PCM must be programmed. PCM Functional Check ^ Refer to System Diagnosis / Diagnostic System Check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Knock Sensor Module > Component Information > Locations PCM With Knock Sensor Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Relays and Modules Computers and Control Systems > Knock Sensor Module > Component Information > Locations > Page 4182 Knock Sensor Module: Service and Repair PCM With Knock Sensor Module Removing Knock Sensor Module From PCM REMOVE OR DISCONNECT 1. Negative battery cable. 2. Powertrain Control Module (PCM) from mounting bracket (refer to PCM removal). 3. Knock sensor (KS) module access cover. 4. Knock sensor module. INSTALL OR CONNECT NOTICE: To prevent possible electrostatic discharge damage to the PCM and KS module, Do Not touch the connector pins or soldered components on the circuit board. 1. Knock senor module. 2. Access cover. 3. PCM to mounting bracket (refer to PCM installation). 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 4188 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4191 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4192 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4193 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4194 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4195 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4196 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4197 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4198 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4199 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4200 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4201 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4202 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4203 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4204 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4205 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4206 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4207 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4208 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4209 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4210 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4211 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4212 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4213 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4214 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4215 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4216 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4217 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4218 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4219 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4220 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4221 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4222 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 4223 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Air Flow Meter/Sensor > Component Information > Diagrams > Page 4224 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4229 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4230 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4231 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4232 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4233 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4234 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4235 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4236 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4237 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4238 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4239 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4240 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4241 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4242 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4243 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4244 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4245 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4246 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4247 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4248 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4249 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4250 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4251 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4252 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4253 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4254 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4255 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4256 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4257 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4258 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4259 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications Coolant Temperature Sensor/Switch (For Computer): Specifications Engine Coolant Temperature (ECT) Sensor ................................................................................................................................................ 23 Nm (17 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 4263 Coolant Temperature Sensor/Switch (For Computer): Locations Left Front Of Engine The engine coolant temperature sensor is located near water pump. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 4264 Coolant Temperature Sensor/Switch (For Computer): Description and Operation Engine Coolant Temperature Sensor The Engine Coolant Temperature (ECT) sensor is a thermistor (a resistor which changes value based on temperature) immersed in the engine coolant stream. Low coolant temperature produces a high resistance while high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the ECT through a resistor in the PCM and measures the voltage. The voltage will be high when the engine is cold and low when the engine is hot. By measuring the voltage. the PCM knows the engine coolant temperature. Engine coolant temperature affects most systems the PCM controls. A failure in the ECT circuit should set either a Diagnostic Trouble Code (DTC) 14 or 15. Remember these DTCs indicate a failure in the engine coolant temperature sensor circuit, so proper use of the chart will lead to either repairing a wiring problem or replacing the sensor to properly repair a problem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Coolant Temperature Sensor/Switch (For Computer) > Component Information > Specifications > Page 4265 Coolant Temperature Sensor/Switch (For Computer): Service and Repair Engine Coolant Temperature Sensor IMPORTANT: Care must be taken when handling engine coolant (ECT) temperature sensor. Damage to engine coolant sensor will affect proper operation of the fuel injection system. REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Relieve coolant pressure. 3. Electrical connector. 4. Carefully back out sensor. INSTALL OR CONNECT 1. Coat threads with sealer. 2. Install sensor in engine. 3. Torque to 23 Nm (17 ft lb). 4. Connect electrical connector. 5. Refill lost coolant. 6. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4270 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4271 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4272 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4273 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4274 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4275 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4276 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4277 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4278 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4279 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4280 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4281 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4282 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4283 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4284 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4285 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4286 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4287 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4288 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4289 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4290 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4291 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4292 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4293 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4294 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4295 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4296 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4297 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4298 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4299 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4300 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Specifications Intake Air Temperature Sensor: Specifications Torque Valve Torque Valve Induction Air Sensor 44 in.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor Intake Air Temperature Sensor: Locations IAT Sensor The Intake Air Temperature (IAT) sensor is located in the air ducting, just forward of the throttle body assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 4306 Intake Air Temperature Sensor: Locations Intake Air Temperature (IAT) Sensor Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Locations > IAT Sensor > Page 4307 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions Intake Air Temperature Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4310 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4311 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4312 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4313 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4314 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4315 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4316 Intake Air Temperature Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4317 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4318 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4319 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4320 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4321 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4322 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4323 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4324 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4325 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4326 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4327 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4328 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4329 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4330 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4331 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4332 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4333 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4334 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4335 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4336 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4337 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4338 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4339 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4340 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4341 Intake Air Temperature (IAT) Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 4342 Intake Air Temperature Sensor: Description and Operation Engine Coolant Temperature (ECT) Sensor The Intake Air Temperature (IAT) sensor is a thermistor (a resistor which changes value based on temperature). It is mounted in the air intake duct. Low temperature produces a high resistance and high temperature causes low resistance. The Powertrain Control Module (PCM) supplies a 5 volt signal to the sensor through a resistor in the PCM and measures the voltage. The voltage will be high when the intake air is cold, and low when the intake manifold air is hot. By measuring the voltage, the PCM knows the intake air temperature. A failure in the IAT sensor circuit should set either a DTC 23 or DTC 25. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Intake Air Temperature Sensor > Component Information > Diagrams > Page 4343 Intake Air Temperature Sensor: Service and Repair REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Electrical connector. 3. Carefully remove sensor from air duct. INSTALL OR CONNECT 1. Install sensor in engine. 2. Connect electrical connector. 3. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Locations > Component Locations > Page 4349 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4352 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4353 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4354 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4355 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4356 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4357 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4358 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4359 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4360 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4361 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4362 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4363 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4364 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4365 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4366 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4367 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4368 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4369 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4370 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4371 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4372 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4373 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4374 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4375 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4376 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4377 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4378 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4379 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4380 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4381 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4382 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4383 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 4384 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 4385 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Knock Sensor > Component Information > Diagrams > Page 4386 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications MAP Sensor Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Electrical Specifications > Page 4391 Manifold Pressure/Vacuum Sensor: Mechanical Specifications Manifold Absolute Pressure (MAP) Bolt ...................................................................................................................................................... 6 Nm (50 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Specifications > Page 4392 Manifold Pressure/Vacuum Sensor: Locations MAP Sensor Location Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions Manifold Pressure/Vacuum Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4395 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4396 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4397 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4398 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4399 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4400 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4401 Manifold Pressure/Vacuum Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4402 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4403 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4404 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4405 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4406 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4407 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4408 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4409 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4410 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4411 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4412 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4413 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4414 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4415 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4416 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4417 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4418 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4419 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4420 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4421 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4422 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4423 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4424 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4425 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4426 Map Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 4427 Manifold Pressure/Vacuum Sensor: Description and Operation MAP Sensor The Manifold Absolute Pressure (MAP) sensor is a pressure sensor that measures changes in intake manifold pressure. The pressure changes as a result of engine load and speed. The MAP sensor converts this to a voltage output. A closed throttle on engine coastdown would produce a relatively low MAP output while a wide-open throttle would produce a high MAP output voltage. This high output voltage is produced because the pressure inside the manifold is the same as outside the manifold, so you measure 100% of outside air pressure. Manifold Absolute Pressure (MAP) is inversely proportional to what you would measure on a vacuum gage. When manifold pressure is high vacuum is low. The MAP sensor is also used to measure barometric pressure under certain conditions which allows the Powertrain Control Module (PCM) to automatically adjust for different altitudes. The PCM sends a 5 volt reference signal to the MAP sensor. As the manifold pressure changes the electrical resistance of the MAP sensor also changes. By monitoring the sensor output voltage the PCM knows the manifold pressure. The PCM uses the MAP sensor to control ignition timing. The MAP sensor is also used for speed density fuel management. When the PCM detects a malfunction with the Mass Air Flow (MAF) sensor circuit the PCM will default to speed density. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Manifold Pressure/Vacuum Sensor > Component Information > Diagrams > Page 4428 Manifold Pressure/Vacuum Sensor: Service and Repair MAP Sensor Location REMOVE OR DISASSEMBLE 1. Negative battery cable. 2. Resonator. 3. Electrical connector. 4. Hold down bolts (2). 5. Sensor from intake manifold. INSTALL OR CONNECT 1. New sensor seal (lightly coated with clean engine oil). 2. Sensor into intake manifold. 3. Hold down bolts. 4. Torque to 6 Nm (50 lb in). 5. Connect electrical connector. 6. Resonator. 7. Connect negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Technical Service Bulletins > Oxygen Sensors - Silica Contamination Oxygen Sensor: Technical Service Bulletins Oxygen Sensors - Silica Contamination Model Year: 1981 Bulletin No: 81-I-37 File In Group: 60 Number: 11 Date: Feb. 81 Subject: Silica Contamination of Oxygen Sensors and Gelation of Oil. Models Affected: All Oxygen sensor performance can deteriorate if certain RTV silicone gasket materials are used. Other RTV's when used with certain oils, may cause gelation of the oil. The degree of performance severity depends on the type of RTV and application of the engine involved. Therefore, when repairing engines where this item is involved, it is important to use either cork composition gaskets or RTV silicone gasket material approved for such use. GMS (General Motors Sealant) or equivalent material can be used. GMS is available through GMPD with the following part numbers: 1052366 3 oz. 1052434 10.14 oz. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications Oxygen Sensor Output Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Specifications > Electrical Specifications > Page 4435 Oxygen Sensor: Mechanical Specifications Heated Oxygen Sensor (HO2S) .......................................................................................................... ......................................................... 41 Nm (30 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH Engine, Left Side Lower Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 4438 Lower Right Side Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Locations > LH > Page 4439 HO2S Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions Oxygen Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4442 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4443 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4444 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4445 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4446 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4447 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4448 Oxygen Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4449 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4450 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4451 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4452 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4453 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4454 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4455 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4456 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4457 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4458 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4459 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4460 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4461 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4462 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4463 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4464 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4465 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4466 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4467 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4468 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4469 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4470 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4471 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4472 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4473 Oxygen Sensor: Electrical Diagrams Heated Oxygen Sensor (HO2S) Sensor Circuit. Right Heated Oxygen Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 4474 Oxygen Sensor: Description and Operation HO2S Cutaway Oxygen Sensor Element The Heated Oxygen Sensor (HO2S) is essentially a small variable battery; it has the ability to produce a low voltage signal that feeds information on engine exhaust oxygen content to the Powertrain Control Module (PCM). The PCM sends a reference signal of 450 mV. The reference signal serves to run the engine when it is in "Open Loop" mode of operation. When the air/fuel ratio is correct the PCM displays 450 mV. When the engine is operating with a rich air/fuel ratio, there is a reduction of free oxygen in the exhaust stream and the oxygen voltage rises above the reference voltage. The HO2S is constructed from a material (zirconia/platinum) that conducts electricity under certain conditions. At operating temperature, 315°C (60o° F), the element becomes a semiconductor. A platinum coating on the outer surface of the element stimulates further combustion of the exhaust gases right Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 4475 at the surface and this helps keep the element up to the desired temperature. The HO2S has an inter cavity which is filled with atmospheric (reference) air. The reference air has approximately 21% oxygen in it. In this electrical circuit this inter cavity is the positive (+) terminal. The outer surface of the element is exposed to the exhaust gas stream. It is the negative (-) or ground terminal. The oxygen concentration differences between the reference air and exhaust gases produce small voltages. A rich exhaust (excessive fuel) has almost no oxygen. When there is a large difference in the amount of oxygen touching the inside and outside surfaces, there is more conduction, and the sensor puts out a voltage signal above 600 mV. With lean exhaust (excessive oxygen) there is about two percent oxygen in the exhaust. This is a smaller difference in oxygen from the outside surfaces which results in less conduction and a voltage signal below 300 mV. The voltages are monitored and used by the PCM to "fine tune" the air/fuel ratio to achieve the ideal mixture desired. When the engine is running lean. the voltage drops below the reference voltage due to excess oxygen in the exhaust stream. The HO2S provides the feedback information for the "Closed Loop" operating mode of the fuel delivery system. The HO2S indicates to the PCM what is happening in the exhaust. It does not cause things to happen. It is a type of gage: Low voltage output = lean mixture = high oxygen content in exhaust; high voltage output = rich mixture = low oxygen content in the exhaust. An open Heated Oxygen Sensor (HO2S) circuit, should set Diagnostic Trouble Code (DTC) 13 or 63. A constant low voltage in the HO2S circuit could set a DTC 44 or 64. A constant high voltage in the circuit should set a DTC 45 or 65. DTCs 44. 45. 64, or 65 could also be set as a result of fuel system problems. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Oxygen Sensor > Component Information > Diagrams > Page 4476 Oxygen Sensor: Service and Repair HO2S Location CAUTION: The Heated Oxygen Sensor (HO2S) uses a permanently attached pigtail and connector. This pigtail should not be removed from the oxygen sensor. Damage or removal of the pigtail or connector could affect proper operation of the oxygen sensor. ^ Take care when handling the oxygen sensor. The in-line electrical connector and louvered end must be kept free off grease, dirt or other contaminants. Also, avoid using cleaning solvents of any type. Be careful not to subject the sensor to sharp impact. REMOVAL: NOTICE: The HO2S may be difficult to remove when engine temperature is below 48° C (120° F). Excessive force may damage threads in exhaust pipe. 1. Disconnect the negative battery cable. 2. Raise vehicle. 3. Disconnect the oxygen sensor electrical connector. 4. Carefully remove the oxygen sensor. INSTALLATION: NOTICE: A special anti-seize compound is used on the oxygen sensor threads. The compound consists of a liquid graphite and glass beads. The graphite will burn away, but the glass beads will remain, making the sensor easier to remove. New or service sensors will already have the compound applied to the threads. If a sensor is removed from an engine, and, if for any reason it is to be reinstalled, the threads must have anti-seize compound applied before reinstallation. 1. Coat the threads of the HO2S with anti-seize compound P/N 5613695, or equivalent if necessary. 2. Install the sensor in the engine, and tighten to 41 Nm (30 ft lb). 3. Connect the electrical connector. 4. Lower vehicle. 5. Connect the negative battery cable. NOTICE: The system has a learning ability which allows it to make corrections for minor variations in the fuel system to improve driveability. When the battery is disconnected the computer's memory is cleared and the learning process has to begin all over again. A change may be noticed in the driving performance of the vehicle. To reset the vehicles learning ability, make sure the engine is at operating temperature and operate the vehicle at part throttle, moderate acceleration, and idle conditions, until normal performance returns. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Locations Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions Power Steering Pressure Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4482 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4483 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4484 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4485 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4486 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4487 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4488 Power Steering Pressure Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4489 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4490 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4491 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4492 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4493 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4494 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4495 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4496 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4497 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4498 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4499 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4500 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4501 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4502 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4503 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4504 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4505 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4506 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4507 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4508 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4509 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4510 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4511 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4512 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 4513 Power Steering Pressure Switch Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Power Steering Pressure Switch > Component Information > Diagrams > Page 4514 Power Steering Pressure Switch: Description and Operation This switch informs the PCM when the power steering pressure is high. During high pressure conditions, the Powertrain Control Module (PCM) will increase idle speed to compensate for the additional load. When the switch closes, the PCM will increase idle speed to compensate for the additional load. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 4518 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 4519 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4522 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4523 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4524 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4525 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4526 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4527 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4528 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4529 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4530 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4531 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4532 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4533 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4534 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4535 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4536 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4537 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4538 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4539 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4540 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4541 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4542 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4543 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4544 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4545 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4546 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4547 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4548 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4549 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4550 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4551 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4552 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4553 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 4554 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 4555 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 4560 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 4561 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4564 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4565 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4566 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4567 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4568 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4569 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4570 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4571 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4572 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4573 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4574 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4575 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4576 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4577 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4578 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4579 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4580 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4581 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4582 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4583 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4584 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4585 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4586 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4587 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4588 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4589 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4590 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4591 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4592 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4593 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4594 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4595 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 4596 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Locations Rear Of Transmission Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions Vehicle Speed Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4602 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4603 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4604 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4605 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4606 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4607 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4608 Vehicle Speed Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4609 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4610 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4611 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4612 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4613 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4614 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4615 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4616 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4617 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4618 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4619 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4620 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4621 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4622 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4623 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4624 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4625 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4626 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4627 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4628 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4629 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4630 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4631 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4632 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description Vehicle Speed Sensor: Description and Operation General Description Vehicle Speed Sensor (2WD) The Vehicle Speed Sensor (VSS) is a pulse counter type input that informs the Powertrain Control Module (PCM) how fast the vehicle is being driven. The VSS system uses an inductive sensor mounted in the tail housing of the transmission and a toothed reluctor wheel on the tail shaft. As the reluctor rotates, the teeth alternately interfere with the magnetic field of the sensor creating an induced voltage pulse. The VSS produces an AC voltage signal that increases with vehicle speed. The PCM processes this signal and sends it to the instrument panel, EVO module, chime module and cruise control module on CKT 817. A malfunction in the VSS system could set Diagnostic Trouble Code (DTC) 24 or DTC 72. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description > Page 4635 Vehicle Speed Sensor: Description and Operation Circuit Operation The Speed Sensor Circuit consists of a magnetic type sensor and wiring. Gear teeth pressed on the Transmission Output Shaft induce an alternating current in the sensor. This sensor generates a sine wave output with a frequency proportional to vehicle speed. The Powertrain Control Module (PCM) converts this signal to an output that is switched to ground at a frequency of 4000 pulses per mile at the DK GRN/WHT wire (CKT 817) which feeds the Turn Signal Alarm, Power Steering Control Module, Instrument Cluster, Cruise Control Module and Radio (Chev only). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Vehicle Speed Sensor: Initial Inspection and Diagnostic Overview PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Sensors and Switches Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 4638 Vehicle Speed Sensor: Symptom Related Diagnostic Procedures Chart #1 Speedometer And Cruise Control Inoperative; Code 24 Not Set Symptom Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 4642 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Specifications > Page 4643 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4646 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4647 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4648 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4649 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4650 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4651 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4652 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4653 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4654 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4655 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4656 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4657 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4658 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4659 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4660 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4661 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4662 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4663 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4664 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4665 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4666 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4667 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4668 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4669 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4670 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4671 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4672 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4673 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4674 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4675 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4676 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4677 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 4678 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Throttle Position Sensor > Component Information > Diagrams > Page 4679 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 4684 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 4685 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4688 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4689 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4690 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4691 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4692 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4693 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4694 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4695 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4696 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4697 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4698 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4699 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4700 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4701 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4702 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4703 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4704 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4705 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4706 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4707 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4708 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4709 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4710 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4711 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4712 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4713 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4714 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4715 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4716 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4717 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4718 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 4719 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 4720 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Locations Rear Of Transmission Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions Vehicle Speed Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4726 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4727 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4728 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4729 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4730 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4731 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4732 Vehicle Speed Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4733 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4734 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4735 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4736 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4737 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4738 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4739 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4740 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4741 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4742 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4743 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4744 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4745 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4746 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4747 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4748 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4749 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4750 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4751 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4752 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4753 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4754 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4755 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4756 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description Vehicle Speed Sensor: Description and Operation General Description Vehicle Speed Sensor (2WD) The Vehicle Speed Sensor (VSS) is a pulse counter type input that informs the Powertrain Control Module (PCM) how fast the vehicle is being driven. The VSS system uses an inductive sensor mounted in the tail housing of the transmission and a toothed reluctor wheel on the tail shaft. As the reluctor rotates, the teeth alternately interfere with the magnetic field of the sensor creating an induced voltage pulse. The VSS produces an AC voltage signal that increases with vehicle speed. The PCM processes this signal and sends it to the instrument panel, EVO module, chime module and cruise control module on CKT 817. A malfunction in the VSS system could set Diagnostic Trouble Code (DTC) 24 or DTC 72. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Description and Operation > General Description > Page 4759 Vehicle Speed Sensor: Description and Operation Circuit Operation The Speed Sensor Circuit consists of a magnetic type sensor and wiring. Gear teeth pressed on the Transmission Output Shaft induce an alternating current in the sensor. This sensor generates a sine wave output with a frequency proportional to vehicle speed. The Powertrain Control Module (PCM) converts this signal to an output that is switched to ground at a frequency of 4000 pulses per mile at the DK GRN/WHT wire (CKT 817) which feeds the Turn Signal Alarm, Power Steering Control Module, Instrument Cluster, Cruise Control Module and Radio (Chev only). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Vehicle Speed Sensor: Initial Inspection and Diagnostic Overview PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Computers and Control Systems > Vehicle Speed Sensor > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 4762 Vehicle Speed Sensor: Symptom Related Diagnostic Procedures Chart #1 Speedometer And Cruise Control Inoperative; Code 24 Not Set Symptom Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Check Valve > Component Information > Specifications Air Injection Check Valve: Specifications Check Valves 17 ft.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Check Valve > Component Information > Specifications > Page 4768 AIR System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Check Valve > Component Information > Specifications > Page 4769 Air Injection Check Valve: Description and Operation The check valves prevent back flow of exhaust gases into the pump in the event of an exhaust backfire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Check Valve > Component Information > Specifications > Page 4770 Air Injection Check Valve: Testing and Inspection A check valve should be inspected whenever the hose is disconnected from a check valve or whenever check valve failure is suspected. (An Air Injection Reaction (AIR) pump that had become inoperative and had shown indications of having exhaust gases in the outlet port would indicate check valve failure.) Blow through the check valve (toward the cylinder head) then attempt to suck back through the check valve. Flow should only be in one direction (toward the exhaust manifold). Replace valve which does not operate properly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Check Valve > Component Information > Specifications > Page 4771 Air Injection Check Valve: Service and Repair Left Side Air LEFT SIDE Remove or Disconnect 1. Check valve clamp. 2. Hose from check valve. 3. Left check valve pipe. 4. Unscrew check valve from air injection pipe. Install or Connect 1. Screw check valve onto air injection pipe. Tighten Valve to 23 Nm (17 lb ft.). 2. Air pipe to exhaust manifold. 3. Air hose to check valve. 4. Check valve clamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Check Valve > Component Information > Specifications > Page 4772 Right Side Air RIGHT SIDE Remove or Disconnect 1. Clamp and air hoses from AIR system right pipe. 2. Check valve clamp. 3. Right check valve pipe. 4. Unscrew check valve from air injection pipe. Install or Connect 1. Screw check valve onto air injection pipe. Tighten Valve to 23 Nm (17 lb ft.). 2. Check valve pipe and clamp. 3. Check AIR system for proper operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Hose/Tube > Component Information > Locations AIR System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Hose/Tube > Component Information > Locations > Page 4776 Air Injection Hose/Tube: Testing and Inspection INSPECT ^ Inspect hoses and/or pipes for deterioration or holes. ^ Inspect all hoses or pipe connections, and clamp torque. ^ Inspect hose and pipe routing. Interference may cause wear. ^ If a leak on the pressure side is suspected, or if a hose or pipe has been disconnected on the pressure side, the connections should be checked for leaks with a soapy water solution. With the Air Injection Reaction (AIR) pump running, bubbles will form if a leak exists. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Hose/Tube > Component Information > Locations > Page 4777 Air Injection Hose/Tube: Service and Repair Air System REMOVE OR DISCONNECT 1. Clamp and air hose to check valve both sides, from cross under pipe. 2. Clamp and air hose to air pump, from cross under pipe. 3. Raise vehicle. 4. Fasteners from air cross under pipe bracket, both sides. 5. Cut cross under pipe near center of oil pan to aid in removal. 6. Cross under pipe. INSTALL OR CONNECT 1. Cross under pipe. New cross under pipe must be cut similarly to old pipe before installation. 2. Use appropriate length of 5/8 heater hose to join both halves of cross under pipe. Clamp both ends of hose securely with stainless steel clamps. 3. Fasteners to AIR cross under pipe bracket, both sides. 4. Lower vehicle. 5. Clamp and AIR hose from AIR pump to cross under pipe 6. Clamp and AIR hose from check valve, both sides, to cross under pipe. 7. Check AIR system for proper operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump > Component Information > Specifications Air Injection Pump: Specifications Reactor Pump Torque Reactor Pump Torque Air Injection Reactor (AIR) Pump 50 in.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump > Component Information > Locations > Air Pump Assembly AIR System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump > Component Information > Locations > Air Pump Assembly > Page 4783 Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump > Component Information > Locations > Page 4784 Air Injection Pump: Description and Operation The Air Injection Reaction (AIR) pump is mounted to the lower left front of the engine and supplies the air to the AIR system. The electric air pump pressurizes air from the engine air cleaner and pumps it to the check valves near the exhaust manifolds. The AIR pump is controlled by the Powertrain Control Module (PCM). Battery voltage to the AIR pump is controlled by the AIR pump relay. An integral stop valve prevents air flow through the pump during "OFF" periods. When the PCM provides a ground circuit for the secondary AIR pump relay, battery voltage is allowed to power up the AIR pump and integral stop valve. The AIR pump motor is protected by a 20 amp fuse and has its own remote ground. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump > Component Information > Locations > Page 4785 Air Injection Pump: Testing and Inspection The Air Injection Reaction (AIR) pump is a regenerative turbine type which is permanently lubricated and requires no periodic maintenance. The engine should be at normal operating temperature in neutral at idle. Using the scan tool select "Miscellaneous Test" then "Output Test." Select "AIR System" in "Output Test" directory. Select Heated Oxygen Sensor (HO2S) voltages for both Bank 1 and Bank 2 HO2S. Enable the "Output Test" for the AIR system. The "Output Test" will energize the AIR pump for only 5 seconds. When the output Test" is enabled, the HO2S voltages for both sensors should remain under 300 mV because air is being directed to the exhaust ports. If the HO2S voltages remain low during the "Output Test," the AIR pump and integral stop valve are operating satisfactorily. If the HO2S voltage does not remain low when the "Output Test" is commanded "ON," proceed as follows. 1. For a seized AIR pump. 2. Hoses, tubes and all connections for leaks and proper routing. 3. For air flow going to the exhaust ports. 4. AIR pump for proper mounting. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump > Component Information > Locations > Page 4786 Air Injection Pump: Service and Repair Air Pump Service REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector from Air Injection Reaction (AIR) pump. 3. Outlet and inlet hoses. 4. Three electric air pump mounting bolts from bracket. INSTALL OR CONNECT: 1. Electric air pump mounting bracket to electric air pump assembly. 2. Three mounting bolts. Tighten Mounting bolts to 5.6 N-m (50 lb in.). 3. Outlet and inlet hoses to pump. 4. Electric connector to air pump. 5. Negative battery cable. 6. Check AIR system for proper operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump Relay > Component Information > Locations Air Injection Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Air Injection Reaction (AIR) System <--> [Air Injection] > Air Injection Pump Relay > Component Information > Locations > Page 4790 Air Injection Pump Relay: Description and Operation Chart C-6 The Powertrain Control Module (PCM) controls operation of the electric air pump relay which in turn controls air availability to the air injection system. The PCM completes the ground to the coil side of the relay. The relay in turn activates the electric air pump and the integral stop valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Catalytic Converter > Component Information > Locations Catalytic Converter Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Locations > Canister Purge Control Solenoid Canister Purge Solenoid Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Locations > Canister Purge Control Solenoid > Page 4799 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions Canister Purge Solenoid: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4802 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4803 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4804 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4805 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4806 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4807 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4808 Canister Purge Solenoid: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4809 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4810 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4811 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4812 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4813 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4814 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4815 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4816 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4817 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4818 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4819 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4820 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4821 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4822 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4823 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4824 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4825 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4826 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4827 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4828 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4829 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4830 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4831 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4832 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4833 Evaporative Canister Purge Solenoid Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Page 4834 Canister Purge Solenoid: Description and Operation Canister Purge Solenoid This system has a remote mounted canister purge control solenoid valve. The Powertrain Control Module (PCM) operates this solenoid valve to control vacuum to the canister. Under cold engine or idle conditions, the solenoid valve is closed, which prevents vacuum from being applied to the canister. The PCM activates (or opens) the solenoid valve and allows purge when: ^ Engine is warm. ^ After the engine has been running a specified period of time. ^ Above a specified road speed. ^ Above a specified throttle opening. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Canister Purge Solenoid > Component Information > Diagrams > Page 4835 Canister Purge Solenoid: Service and Repair Canister Purge Solenoid REMOVE OR DISCONNECT 1. Negative battery cable. 2. Fastener from ignition test connector. 3. Electrical connector and hoses from solenoid. 4. Bracket and solenoid from intake manifold. INSTALL OR CONNECT 1. Solenoid to intake manifold Tighten ^ Bolt to intake manifold to 5.8 Nm (52 lb in.). 2. Hoses and electrical connector to solenoid 3. Ignition test connector to bracket 4. Negative battery cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Check Valve > Component Information > Locations Canister And Valve Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Check Valve > Component Information > Locations > Page 4839 Evaporative Check Valve: Description and Operation EVAP Pressure Control Valve This system uses an in-line Evaporative Emissions (EVAP) pressure control valve as a pressure relief valve. When vapor pressure in the tank exceeds approximately 5 kPa (.7 psi) the diaphragm valve opens, allowing vapors to vent to the canister. A 1.14 mm (0.045 inch) orifice in the passage leading to the canister tube causes pressure to drop slowly, preventing the valve from oscillating (buzzing). When the tank pressure drops below 5 kPa (.7 psi), the valve closes causing vapors to be held in the fuel tank. RESULTS OF INCORRECT OPERATION ^ Poor idle, stalling and poor driveability can be caused by: Inoperative purge solenoid valve. - Damaged canister. - Hoses split, cracked and, or not connected to the proper tubes. ^ Evidence of fuel loss or fuel vapor odor can be caused by: Liquid fuel leaking from fuel lines. - Cracked or damaged canister. - Inoperative canister control valve. - Disconnected, misrouted, kinked, deteriorated or damaged vapor hoses, or control hoses. If the solenoid valve is open. or is not receiving power, the canister can purge to the intake manifold at the incorrect time. This can allow extra fuel during warm-up, which can cause rough or unstable idle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Check Valve > Component Information > Locations > Page 4840 Evaporative Check Valve: Testing and Inspection With a hand vacuum pump, apply approximately 51 kPa (15" Hg) to the control vacuum tube. After ten seconds, there should be at least 17 kPa (5" Hg) vacuum remaining. Be sure the hand vacuum pump being used does not have an internal leak and the hose connections to control vacuum tube and pump are secure. If after 10 seconds there is less than 17 kPa (5" Hg) vacuum, the valve must be replaced. With 51 kPa (15" Hg) vacuum still applied to the control vacuum tube, attach a short piece of hose to the valve's tank tube side. Blow into the tube. You should feel the air pass through the valve. If air does not pass through, the valve must be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Emission Control Canister > Component Information > Locations Canister And Valve Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Emission Control Canister > Component Information > Locations > Page 4844 Evaporative Emission Control Canister: Description and Operation Fuel Vapor Canister The Evaporative Emission (EVAP) control system uses a 1500 cc charcoal canister to absorb fuel vapors from the gas tank. When gasoline vapor builds enough to overcome the spring tension of the EVAP pressure control valve, the vapor will flow to the canister where it is absorbed and stored by the charcoal. Under certain operating conditions the Powertrain Control Module (PCM) will command the purge solenoid valve to open. This allows the vapor to flow into the intake manifold for combustion. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Emission Control Canister > Component Information > Locations > Page 4845 Evaporative Emission Control Canister: Testing and Inspection Perform a visual inspection of the Canister, replace if cracked or damaged. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Emission Control Canister > Component Information > Locations > Page 4846 Evaporative Emission Control Canister: Service and Repair Canister And Valve Location REMOVE OR DISCONNECT 1. Negative battery cable. 2. Raise vehicle 3. Access panel. 4. Hoses from canister. 5. Canister from bracket. 6. Canister from vehicle. INSTALL OR CONNECT 1. Canister to vehicle. 2. Canister to bracket. 3. Hoses to canister. 4. Access panel. 5. Lower vehicle. 6. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Emissions Hose > Component Information > Technical Service Bulletins > Fuel Odor - Right Hand Side of Passenger Compartment Evaporative Emissions Hose: Technical Service Bulletins Fuel Odor - Right Hand Side of Passenger Compartment File In Section: 6E - Engine Fuel & Emission Bulletin No.: 67-65-18 Date: March, 1996 Subject: Fuel Odor Near the Right Hand Side of the Passenger Compartment (Reroute Canister Fresh Air Hose) Models: 1994-95 Buick Roadmaster 1994-95 Cadillac Fleetwood 1994-95 Chevrolet Caprice, Impala SS with 4.3L, 5.7L Engine (VINs W, P - RPOs L99, LT1) and with Automatic HYDRA-MATIC 4L60-E Transmission Condition Some owners may comment of fuel odor near the RH (Right Hand) side of the passenger compartment. Cause Under high ambient temperatures and slow speed driving conditions, (i.e. stop and go traffic) fuel odor from the canister fresh air inlet hose located in the RH side fender well may carryover to RH side of the passenger compartment. Correction Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Emissions Hose > Component Information > Technical Service Bulletins > Fuel Odor - Right Hand Side of Passenger Compartment > Page 4851 Relocate the canister fresh air hose to the front radiator support. See Figure 1. Warranty Information For vehicles repaired under warranty, use: Labor Operation Labor Time T-2495 0.4 hr Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Fuel Vapor Return Hose > Component Information > Description and Operation Evaporative Fuel Vapor Return Hose: Description and Operation The evaporative emission (EVAP) pipe extends from the fuel sender assembly to the evaporative emission canister. It is made up of nylon pipe and is connected to the fuel sender assembly and the evaporative emission canister with fuel resistant rubber hoses. WARNING: To Reduce the Risk of Fire and Personal Injury: ^ Always cover nylon vapor pipes with a wet towel before using a torch near them. Also, never expose the vehicle to temperatures higher then 115° C (239° F) for more than one hour, or more than 90° C (194° F) for any extended period. ^ Take care not to nick or scratch the nylon vapor pipes. If damaged, they must be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Fuel Vapor Return Hose > Component Information > Description and Operation > Page 4855 Evaporative Fuel Vapor Return Hose: Service and Repair Evaporative Emissions (EVAP) Pipe Replacement NOTICE: ^ If nylon pipes becomes kinked, and cannot be straightened, they must be replaced. ^ Do Not attempt to repair sections of nylon pipes. If damaged, replace. ^ When replacing evaporative emissions (EVAP) pipes, always replace them with original equipment or parts that meet the GM specifications for those parts. ^ When replacing EVAP hoses always replace them with original equipment or parts meeting GM specifications, use only reinforced fuel-resistant hose which is identified with the word "Fluoroelastomer" or "GM 6163-M" on the hose. REMOVE OR DISCONNECT 1. Raise vehicle. 2. Fuel feed, return, and EVAP pipe underbody retainer. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Evaporative Emissions System > Evaporative Fuel Vapor Return Hose > Component Information > Description and Operation > Page 4856 3. EVAP pipe clamp at fuel sender assembly. 4. EVAP pipe retaining clips. ^ Note position of EVAP pipe for installation. 5. Lower vehicle. 6. EVAP pipe hose end clamp at EVAP canister. 7. Forward pipe assembly retaining clips. 8. EVAP pipe. INSTALL OR CONNECT 1. Insert rear end of EVAP pipe into top forward frame hole. Load until formed pipe/conduit reaches into hole. 2. Forward pipe assembly retaining clips. 3. EVAP pipe hose end to EVAP canister. Secure with clamp. 4. Raise vehicle. 5. Position new EVAP pipe in same position as noted during disassembly and install retaining clips. 6. EVAP pipe clamp at fuel sender assembly. 7. Fuel feed, return, and EVAP pipe underbody retainer. 8. Lower vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Control Solenoid > Component Information > Specifications EGR Control Solenoid: Specifications Bracket Nut Torque Bracket Nut Torque Solenoid Valve and Bracket Nut 25 ft.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Control Solenoid > Component Information > Specifications > Page 4861 Engine Left Side Upper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Locations EGR Solenoid Valve Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions EGR Electronic Vacuum Regulator Solenoid: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4867 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4868 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4869 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4870 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4871 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4872 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4873 EGR Electronic Vacuum Regulator Solenoid: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4874 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4875 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4876 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4877 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4878 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4879 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4880 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4881 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4882 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4883 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4884 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4885 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4886 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4887 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4888 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4889 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4890 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4891 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4892 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4893 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4894 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4895 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4896 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4897 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 4898 Exhaust Gas Recirculation (EGR) Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Page 4899 EGR Electronic Vacuum Regulator Solenoid: Description and Operation The Exhaust Gas Recirculation (EGR) vacuum control has a vacuum control solenoid that is controlled by Pulse Width Modulation (PWM). This means that the Powertrain Control Module (PCM) turns the solenoid "OFF" and "ON" many times a second and varies the amount of "ON" time (pulse width) to vary the amount ported manifold vacuum to the EGR valve. The PCM uses RPM and information from the following sensors to regulate the EGR solenoid valve: ^ Engine Coolant Temperature (ECT) sensor. ^ Intake Air Temperature (IAT) sensor. ^ Throttle Position (TP) sensor. ^ Manifold Absolute Pressure (MAP) sensor. ^ Park/Neutral Position (PNP) switch. ^ Vehicle Speed Sensor (VSS). Grounding the Data Link Connector (DLC) output / field service enable terminal with the ignition "ON" and the engine not running will energize the solenoid valve and allow vacuum to the EGR valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Electronic Vacuum Regulator Solenoid > Component Information > Diagrams > Page 4900 EGR Electronic Vacuum Regulator Solenoid: Service and Repair EGR Solenoid Valve REMOVE OR DISCONNECT 1. Negative battery cable 2. Electrical connector 3. Vacuum hoses 4. Nut and solenoid INSTALL OR CONNECT 1. Solenoid and bracket Tighten Nut to 34 Nm (25 lb ft.). 2. Vacuum hoses 3. Electrical connector 4. Negative battery cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Valve > Component Information > Specifications EGR Valve: Specifications Exhaust Gas Recirculation Valve Bolts 16 ft.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Valve > Component Information > Specifications > Page 4904 EGR Valve Service Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Valve > Component Information > Specifications > Page 4905 EGR Valve: Application and ID EGR Valve Identification EXHAUST GAS RECIRCULATION (EGR) VALVE IDENTIFICATION ^ Negative backpressure EGR valves are stamped with a "N" on the top side of the valve after the part number. ^ Positive backpressure EGR valves are stamped with a "P" on the top side of the valve after the part number. ^ Port EGR valves will have no identification stamped after the part number. When replacing an EGR valve, always check for correct part number in the part catalog or supplemental bulletins. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Valve > Component Information > Specifications > Page 4906 EGR Valve: Description and Operation The Exhaust Gas Recirculation (EGR) valve used on this engine is a negative backpressure valve. It varies the amount of exhaust gas flow into the manifold depending on manifold vacuum and variations in exhaust backpressure. The diaphragm on this EGR valve has an internal vacuum bleed hole which is held closed by a small spring when there is no exhaust backpressure the amount of vacuum to the valve is controlled by an Powertrain Control Module (PCM) controlled solenoid valve. Engine vacuum opens the EGR valve again the pressure of a large spring. When vacuum combines with negative exhaust backpressure, the vacuum bleed hole opens and the EGR valve closes. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Valve > Component Information > Specifications > Page 4907 EGR Valve: Testing and Inspection Too much Exhaust Gas Recirculation (EGR) flow dilutes the fresh intake air/fuel mixture, causing the engine to run roughly or stall. With too much EGR flow (at idle, cruise, or cold operation) tends to weaken combustion and may result in any of the following conditions: ^ Engine stops after cold start. ^ Engine stops at idle after deceleration. ^ Vehicle surges during cruise. ^ Rough idle. Too little or no EGR flow allows combustion temperatures to get too high during acceleration and load conditions. This could cause: ^ Spark knock (detonation). ^ Engine overheating. ^ Emission test failure. For diagnosis of the EGR system refer to Computers and Control Systems / System Diagnosis / Procedures / Diagnostic chart C-7. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Exhaust Gas Recirculation > EGR Valve > Component Information > Specifications > Page 4908 EGR Valve: Service and Repair EGR Valve Service REMOVE OR DISCONNECT 1. Negative battery cable. 2. Vacuum line. 3. Retaining nuts. 4. Exhaust Gas Recirculation (EGR) valve. INSPECT If EGR passages in the inlet manifold indicate excessive build-up of deposits, the passages should be cleaned. Care should be taken to ensure that all loose particles are completely removed to prevent them from clogging the EGR valve or from being ingested into the engine. CLEAN 1. With a wire wheel, buff the exhaust deposits from the mounting surface and around the valve. 2. Look for exhaust deposits in the valve outlet. Remove deposit build-up with a screwdriver. 3. Clean mounting surfaces of intake manifold and valve assembly. INSTALL OR CONNECT 1. EGR valve on intake manifold using a new gasket Tighten Bolts to 22 Nm (16 lb ft.). 2. Vacuum hose to valve 3. Negative battery cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Positive Crankcase Ventilation > Positive Crankcase Ventilation Valve > Component Information > Locations Crankcase Ventilation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Positive Crankcase Ventilation > Positive Crankcase Ventilation Valve > Component Information > Locations > Page 4913 Positive Crankcase Ventilation Valve: Testing and Inspection If an engine is idling rough, check for a clogged positive crankcase ventilation (PCV) valve or plugged hose. Replace as required. Use the following procedure: 1. Remove PCV valve from intake manifold. 2. Run the engine at idle. 3. Place your thumb over end of valve to check for vacuum. If there is no vacuum at the valve, check for plugged hoses or manifold port, or PCV valve. Replace plugged or deteriorated hoses. 4. Turn "OFF" the engine and remove PCV valve. Shake valve and listen for the rattle of check needle inside the valve. If valve does not rattle, replace valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Positive Crankcase Ventilation > Positive Crankcase Ventilation Valve > Component Information > Locations > Page 4914 Positive Crankcase Ventilation Valve: Service and Repair Crankcase Ventilation REMOVE OR DISCONNECT 1. Remove positive crankcase ventilation (PCV) valve from valve cover. 2. Remove PCV valve from vacuum hose. INSPECT 1. Ensure hoses and vacuum passages are free of obstruction. Ensure PCV valve is not stuck or bound. INSTALL OR CONNECT: 1. Reverse removal procedures to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Relays and Modules - Emission Control Systems > Air Injection Pump Relay > Component Information > Locations Air Injection Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Emission Control Systems > Relays and Modules - Emission Control Systems > Air Injection Pump Relay > Component Information > Locations > Page 4919 Air Injection Pump Relay: Description and Operation Chart C-6 The Powertrain Control Module (PCM) controls operation of the electric air pump relay which in turn controls air availability to the air injection system. The PCM completes the ground to the coil side of the relay. The relay in turn activates the electric air pump and the integral stop valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure > Diagnostic Connector - Fuel Pump > Component Information > Locations Diagnostic Connector - Fuel Pump: Locations The fuel pump test connector is located in the engine compartment near the A/C accumulator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations Fuel Pressure Test Port Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations > Page 4928 Fuel Pressure Test Port: Service and Repair Fuel Test Port Valve CLEAN ^ Area around fuel pressure connection with GM X-3OA or equivalent. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery System / Service and Repair. 3. Fuel pressure connection valve assembly. INSTALL OR CONNECT 1. Fuel pressure connection valve assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ Turn ignition switch to the "ON" position for two seconds, then turn to the "OFF" position for ten seconds. Again turn to "ON" position, and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Release > System Information > Service and Repair Fuel Pressure Release: Service and Repair WARNING: - To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing fuel system components. - After relieving the fuel system pressure a small amount of fuel may be released when servicing fuel lines or connections. In order to reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting, to catch any fuel that may leak out. Place the shop towel in an approved container when the disconnect is complete. Fuel Pressure Test Port PROCEDURE: 1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine. 2. Loosen the fuel filler cap to relieve tank pressure. 3. Connect the J 34730-1 fuel pressure gauge to the fuel pressure connection on the fuel rail. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage. 4. Install a bleed hose into an approved container and open the valve slowly to relieve system pressure. Fuel connections are now safe for servicing. 5. Drain any fuel remaining in the gauge into an approved container. NOTE: After repairs are complete, tighten the fuel cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Speed > System Information > Specifications Idle Speed: Specifications The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Speed > System Information > Specifications > Page 4935 Idle Speed: Adjustments The Idle Speed is controlled by the Powertrain Control Module and is not adjustable. If Idle Speed is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air/Fuel Mixture > System Information > Specifications Air/Fuel Mixture: Specifications The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air/Fuel Mixture > System Information > Specifications > Page 4939 Air/Fuel Mixture: Adjustments The Air / Fuel mixture is controlled by the Powertrain Control Module and is not adjustable. If Air / Fuel mixture is incorrect begin diagnosis at Powertrain Management / System Diagnosis / Flow of Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > Recalls for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal Technical Service Bulletin # 95C23 Date: 950602 Recall - Excessive Friction in Accelerator Pedal CHEVROLET No: 95-C-23 Issued: 06/01/95 Subject: PRODUCT SAFETY CAMPAIGN 95-C-23 ACCELERATOR PEDAL ASSEMBLY Model and Year: 1994-1995 CHEVROLET CAPRICE/IMPALA TO: All Chevrolet/Geo Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle which is subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonably equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solutions, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the attached copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact the National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1994-95 Chevrolet Caprice and Impala model vehicles may have been built with a defective accelerator pedal assembly which causes the vehicles to fail to conform to the requirements of the Federal Motor Vehicle Safety Standard (FMVSS) 124, "Accelerator Control Systems". Under some circumstances at low temperatures, there may be excessive friction in the accelerator pedal assembly. If there is excessive friction in the pedal assembly, in the event of a failure of a throttle return spring the engine speed may not return to idle as specified in FMVSS 124. To correct this condition, dealers are to replace the accelerator pedal assembly. VEHICLES INVOLVED Involved are certain 1994-95 Chevrolet Caprice a Impala model vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign. These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information A preshipment of parts will be sent to involved dealers the week of May 29, 1995. Preshipment parts will be charged to the dealers, open parts account. Additional parts required to complete this campaign are to be obtained from General Motors Service Parts Operations (GMSPO). To ensure these parts will be obtained as soon as possible, they should be ordered from GMSPO on a "C.I.O." order with no special instruction code, but on an advise code (2). All Goodwrench parts system test dealers should order on a "VIP" order. Quantity Part Number Description Vehicle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > Recalls for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4948 12553725 Accelerator Pedal Assembly 1 Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the owners letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter In summary, whenever a vehicle subject to this campaign enters your vehicle inventory, or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. This bulletin is notice to you that the new motor vehicles included in this campaign may not comply with the standard identified above Under Section 108 of the National Traffic and Motor Vehicle Safety Act, it is illegal for a dealer to sell a new motor vehicle which the dealer knows does not comply with an applicable Federal Motor Vehicle Safety Standard. As a consequence, if you sell any of these motor vehicles without first performing the campaign correction, your dealership may be subject to a civil penalty up to $1,000 for each such sale. Service Procedure 1. Place ignition in full lock position and set parking brake. 2. Disconnect accelerator cable from accelerator pedal assembly. 3. Remove three (3) screws from accelerator pedal assembly. 4. Remove instrument panel/body harness connector mounting screws and connector from accelerator pedal assembly 5. Remove accelerator pedal assembly from dash panel. 6. Install instrument panel/body harness connector mounting screws and connector to new accelerator Pedal assembly. Torque to 7 Nm (62 lb. in). 7. Install new accelerator pedal assembly to dash panel. Torque to 2.8 Nm (25 lb. in). Important: Insure accelerator pedal assembly plate is positioned flat against dash panel. Other material such as carpeting, insulation, etc. must NOT interfere with the accelerator pedal assembly plate and the dash panel. The floor carpet assembly in pedal area must be positioned to lay flat and be free of wrinkles and bunches. 8. Connect accelerator cable to accelerator pedal assembly. TO INSURE THAT THE THROTTLE SYSTEM OPERATES PROPERLY AFTER THE ABOVE SERVICE PROCEDURE, PERFORM AN INSPECTION OF THE FOLLOWING THROTTLE COMPONENTS: 9. Cable assembly must not be kinked or damaged in any way during assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > Recalls for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4949 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > Recalls for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4950 10. Inspect the accelerator cable and throttle return spring at the throttle lever on the throttle body. See illustrations. Reposition accelerator cable and throttle return spring if necessary. 11. Check for complete throttle opening and closing positions by operating accelerator pedal. Throttle must operate freely without binding between full closed throttle and full open throttle. 12. Install Campaign Identification Label. Campaign ID Label & Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Each "Campaign Identification Label", is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional "Campaign Identification Labels" can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean, dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > Recalls for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4951 Net price plus 40% of all parts required for the repair. Refer to the Chevrolet Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1994-95 Chevrolet Caprice and Impala model vehicles may have been built with a defective accelerator pedal assembly which causes the vehicles to fail to conform to the requirements of the Federal Motor Vehicle Safety Standard (FMVSS) 124 "Accelerator Control Systems". Under some circumstances at low temperatures, there may be excessive friction in the accelerator pedal assembly. If there is excessive friction in the pedal assembly, in the event of a failure of a throttle return spring the engine speed may not return to idle as specified in FMVSS 124. WHAT WE WILL DO To correct this condition, it is necessary to install a new accelerator pedal assembly. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date and so the dealer may order the necessary parts for the repair. Instructions for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 20 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the Administrator, National Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your safety and continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal Technical Service Bulletin # 95C23 Date: 950602 Recall - Excessive Friction in Accelerator Pedal CHEVROLET No: 95-C-23 Issued: 06/01/95 Subject: PRODUCT SAFETY CAMPAIGN 95-C-23 ACCELERATOR PEDAL ASSEMBLY Model and Year: 1994-1995 CHEVROLET CAPRICE/IMPALA TO: All Chevrolet/Geo Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle which is subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonably equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solutions, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the attached copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact the National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1994-95 Chevrolet Caprice and Impala model vehicles may have been built with a defective accelerator pedal assembly which causes the vehicles to fail to conform to the requirements of the Federal Motor Vehicle Safety Standard (FMVSS) 124, "Accelerator Control Systems". Under some circumstances at low temperatures, there may be excessive friction in the accelerator pedal assembly. If there is excessive friction in the pedal assembly, in the event of a failure of a throttle return spring the engine speed may not return to idle as specified in FMVSS 124. To correct this condition, dealers are to replace the accelerator pedal assembly. VEHICLES INVOLVED Involved are certain 1994-95 Chevrolet Caprice a Impala model vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign. These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information A preshipment of parts will be sent to involved dealers the week of May 29, 1995. Preshipment parts will be charged to the dealers, open parts account. Additional parts required to complete this campaign are to be obtained from General Motors Service Parts Operations (GMSPO). To ensure these parts will be obtained as soon as possible, they should be ordered from GMSPO on a "C.I.O." order with no special instruction code, but on an advise code (2). All Goodwrench parts system test dealers should order on a "VIP" order. Quantity Part Number Description Vehicle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4957 12553725 Accelerator Pedal Assembly 1 Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the owners letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter In summary, whenever a vehicle subject to this campaign enters your vehicle inventory, or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. This bulletin is notice to you that the new motor vehicles included in this campaign may not comply with the standard identified above Under Section 108 of the National Traffic and Motor Vehicle Safety Act, it is illegal for a dealer to sell a new motor vehicle which the dealer knows does not comply with an applicable Federal Motor Vehicle Safety Standard. As a consequence, if you sell any of these motor vehicles without first performing the campaign correction, your dealership may be subject to a civil penalty up to $1,000 for each such sale. Service Procedure 1. Place ignition in full lock position and set parking brake. 2. Disconnect accelerator cable from accelerator pedal assembly. 3. Remove three (3) screws from accelerator pedal assembly. 4. Remove instrument panel/body harness connector mounting screws and connector from accelerator pedal assembly 5. Remove accelerator pedal assembly from dash panel. 6. Install instrument panel/body harness connector mounting screws and connector to new accelerator Pedal assembly. Torque to 7 Nm (62 lb. in). 7. Install new accelerator pedal assembly to dash panel. Torque to 2.8 Nm (25 lb. in). Important: Insure accelerator pedal assembly plate is positioned flat against dash panel. Other material such as carpeting, insulation, etc. must NOT interfere with the accelerator pedal assembly plate and the dash panel. The floor carpet assembly in pedal area must be positioned to lay flat and be free of wrinkles and bunches. 8. Connect accelerator cable to accelerator pedal assembly. TO INSURE THAT THE THROTTLE SYSTEM OPERATES PROPERLY AFTER THE ABOVE SERVICE PROCEDURE, PERFORM AN INSPECTION OF THE FOLLOWING THROTTLE COMPONENTS: 9. Cable assembly must not be kinked or damaged in any way during assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4958 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4959 10. Inspect the accelerator cable and throttle return spring at the throttle lever on the throttle body. See illustrations. Reposition accelerator cable and throttle return spring if necessary. 11. Check for complete throttle opening and closing positions by operating accelerator pedal. Throttle must operate freely without binding between full closed throttle and full open throttle. 12. Install Campaign Identification Label. Campaign ID Label & Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Each "Campaign Identification Label", is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional "Campaign Identification Labels" can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean, dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Accelerator Controls: > 95C23 > Jun > 95 > Recall - Excessive Friction in Accelerator Pedal > Page 4960 Net price plus 40% of all parts required for the repair. Refer to the Chevrolet Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1994-95 Chevrolet Caprice and Impala model vehicles may have been built with a defective accelerator pedal assembly which causes the vehicles to fail to conform to the requirements of the Federal Motor Vehicle Safety Standard (FMVSS) 124 "Accelerator Control Systems". Under some circumstances at low temperatures, there may be excessive friction in the accelerator pedal assembly. If there is excessive friction in the pedal assembly, in the event of a failure of a throttle return spring the engine speed may not return to idle as specified in FMVSS 124. WHAT WE WILL DO To correct this condition, it is necessary to install a new accelerator pedal assembly. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date and so the dealer may order the necessary parts for the repair. Instructions for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 20 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the Administrator, National Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your safety and continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > Page 4961 Accelerator Controls: Description and Operation The accelerator control system is cable type. There are no linkage adjustments. Therefore, the specific cable must be used. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Accelerator Controls <--> [Accelerator Pedal] > Component Information > Technical Service Bulletins > Page 4962 Accelerator Controls: Service and Repair Accelerator Pedal REMOVE OR DISCONNECT 1. Accelerator pedal push on nut. 2. accelerator pedal from accelerator pedal lever. INSTALL OR CONNECT 1. accelerator pedal and spring to accelerator pedal lever. 2. New push on nut to accelerator pedal lever. INSPECT ^ Check for complete throttle opening and closing positions by operating accelerator pedal. Also check for poor carpet fit under the accelerator pedal. Throttle should operate freely without blind between full closed and wide open throttle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Cleaner Fresh Air Duct/Hose > Component Information > Locations Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: Customer Interest Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Customer Interest for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 4975 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Air Filter Element: All Technical Service Bulletins Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Air Filter Element: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 4981 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 4982 Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 4983 Air Filter Element: Service and Repair Air Ducting Air Intake System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Cleaner Housing > Air Filter Element > Component Information > Technical Service Bulletins > Page 4984 REMOVE OR DISCONNECT 1. Loosen wing nuts at front of air cleaner housing. 2. Lift air cleaner lid, Mass Air Flow (MAF) sensor and resonator as a unit. 3. Remove air filter element. INSTALL OR CONNECT 1. Install air filter element. 2. Move air cleaner lid, MAF sensor and resonator into place. 3. Tighten wing nuts. 4. Check clamps at MAF sensor and tighten if necessary. 5. Check joints between duct, resonators and throttle body for possible air leaks. Repair if necessary. NOTICE: If the Mass Air Flow (MAF) sensor is installed backwards, the system will go rich. An arrow cast into the plastic portion of the sensor indicates proper air flow direction. The arrow must point toward the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 4989 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4992 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4993 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4994 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4995 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4996 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4997 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4998 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 4999 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5000 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5001 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5002 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5003 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5004 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5005 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5006 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5007 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5008 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5009 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5010 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5011 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5012 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5013 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5014 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5015 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5016 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5017 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5018 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5019 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5020 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5021 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5022 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5023 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 5024 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 5025 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Diagnostic Connector - Fuel Pump > Component Information > Locations Diagnostic Connector - Fuel Pump: Locations The fuel pump test connector is located in the engine compartment near the A/C accumulator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Fuel System - TOP TIER Detergent Gasoline (Canada) Fuel: Technical Service Bulletins Fuel System - TOP TIER Detergent Gasoline (Canada) INFORMATION Bulletin No.: 05-06-04-022G Date: October 27, 2010 Subject: TOP TIER Detergent Gasoline Information and Available Brands (Deposits, Fuel Economy, No Start, Power, Performance, Stall Concerns) - Canada ONLY Models: 2011 and Prior GM Passenger Cars and Trucks (Canada Only) Supercede: This bulletin is being revised to update the model years and include an additional gasoline brand as a TOP TIER source. Please discard Corporate Bulletin Number 05-06-04-022F (Section 06 - Engine/Propulsion System). In the U.S., refer to the latest version of Corporate Bulletin Number 04-06-04-047I. A new class of fuel called TOP TIER Detergent Gasoline is appearing at retail stations of some fuel marketers. This gasoline meets detergency standards developed by six automotive companies. All vehicles will benefit from using TOP TIER Detergent Gasoline over gasoline containing the "Lowest Additive Concentration" recommended by the Canadian General Standards Board (CGSB). Those vehicles that have experienced deposit related concerns may especially benefit from use of TOP TIER Detergent Gasoline. Intake valve: 16,093 km (10,000 mi) with TOP TIER Detergent Gasoline Intake valve: 16,093 km (10,000 mi) with Minimum Additive recommended by the CGSB Top Tier Fuel Availability Chevron was the first to offer TOP TIER Detergent Gasoline in Canada. Shell became the first national gasoline retailer to offer TOP TIER Detergent Gasoline across Canada. Petro-Canada began offering TOP TIER Detergent Gasoline nationally as of October 1, 2006. Sunoco began offering TOP TIER Detergent Gasoline in March of 2007. Esso began offering TOP TIER Detergent Gasoline in May of 2010. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Fuel System - TOP TIER Detergent Gasoline (Canada) > Page 5033 Gasoline Brands That Currently Meet TOP TIER Detergent Gasoline Standards The following gasoline brands meet the TOP TIER Detergent Gasoline Standards in all octane grades : Chevron Canada (markets in British Columbia and western Alberta) - Shell Canada (nationally) - Petro-Canada (nationally) - Sunoco-Canada (Ontario) - Esso-Canada (nationally) What is TOP TIER Detergent Gasoline? TOP TIER Detergent Gasoline is a new class of gasoline with enhanced detergency and no metallic additives. It meets new, voluntary deposit control standards developed by six automotive companies that exceed the detergent recommendations of Canadian standards and does not contain metallic additives, which can damage vehicle emission control components. Where Can TOP TIER Detergent Gasoline Be Purchased? The TOP TIER program began in the U.S. and Canada on May 3, 2004. Some fuel marketers have already joined and introduced TOP TIER Detergent Gasoline. This is a voluntary program and not all fuel marketers will offer this product. Once fuel marketers make public announcements, they will appear on a list of brands that meet the TOP TIER standards. Who developed TOP TIER Detergent Gasoline standards? TOP TIER Detergent Gasoline standards were developed by six automotive companies: BMW, General Motors, Honda, Toyota, Volkswagen and Audi. Why was TOP TIER Detergent Gasoline developed? TOP TIER Detergent Gasoline was developed to increase the level of detergent additive in gasoline. In the U.S., government regulations require that all gasoline sold in the U.S. contain a detergent additive. However, the requirement is minimal and in many cases, is not sufficient to keep engines clean. In Canada, gasoline standards recommend adherence to U.S. detergency requirements but do not require it. In fact, many brands of gasoline in Canada do not contain any detergent additive. In order to meet TOP TIER Detergent Gasoline standards, a higher level of detergent is needed than what is required or recommended, and no metallic additives are allowed. Also, TOP TIER was developed to give fuel marketers the opportunity to differentiate their product. Why did the six automotive companies join together to develop TOP TIER? All six corporations recognized the benefits to both the vehicle and the consumer. Also, joining together emphasized that low detergency and the intentional addition of metallic additives is an issue of concern to several automotive companies. What are the benefits of TOP TIER Detergent Gasoline? TOP TIER Detergent Gasoline will help keep engines cleaner than gasoline containing the "Lowest Additive Concentration" recommended by Canadian standards. Clean engines help provide optimal fuel economy and engine performance, and also provide reduced emissions. Also, the use of TOP TIER Detergent Gasoline will help reduce deposit related concerns. Who should use TOP TIER Detergent Gasoline? All vehicles will benefit from using TOP TIER Detergent Gasoline over gasoline containing the "Lowest Additive Concentration" recommended by Canadian standards. Those vehicles that have experienced deposit related concerns may especially benefit from use of TOP TIER Detergent Gasoline. More information on TOP TIER Detergent Gasoline can be found at this website, http://www.toptiergas.com/. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Fuel System - TOP TIER Detergent Gasoline (Canada) > Page 5034 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Fuel System - TOP TIER Detergent Gasoline (Canada) > Page 5035 Fuel: Technical Service Bulletins Fuel System - 'TOP TIER' Detergent Gasoline Information INFORMATION Bulletin No.: 04-06-04-047I Date: August 17, 2009 Subject: TOP TIER Detergent Gasoline (Deposits, Fuel Economy, No Start, Power, Performance, Stall Concerns) - U.S. Only Models: 2010 and Prior GM Passenger Cars and Trucks (including Saturn) (U.S. Only) 2003-2010 HUMMER H2 (U.S. Only) 2006-2010 HUMMER H3 (U.S. Only) 2005-2009 Saab 9-7X (U.S. Only) Supercede: This bulletin is being revised to add model years and additional sources to the Top Tier Fuel Retailers list. Please discard Corporate Bulletin Number 04-06-04-047H (Section 06 Engine/Propulsion System). In Canada, refer to Corporate Bulletin Number 05-06-04-022F. A new class of fuel called TOP TIER Detergent Gasoline is appearing at retail stations of some fuel marketers. This gasoline meets detergency standards developed by six automotive companies. All vehicles will benefit from using TOP TIER Detergent Gasoline over gasoline containing the "Lowest Additive Concentration" set by the EPA. Those vehicles that have experienced deposit related concerns may especially benefit from the use of TOP TIER Detergent Gasoline. Intake valve: - 10,000 miles with TOP TIER Detergent Gasoline Intake valve: - 10,000 miles with Legal Minimum additive Gasoline Brands That Currently Meet TOP TIER Detergent Gasoline Standards As of August 1, 2009, all grades of the following gasoline brands meet the TOP TIER Detergent Gasoline Standards: - Chevron - Chevron-Canada - QuikTrip - Conoco Phillips 66 - 76 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Fuel System - TOP TIER Detergent Gasoline (Canada) > Page 5036 - Shell - Shell-Canada - Entec Stations located in the greater Montgomery, Alabama area. - MFA Oil Company located throughout Missouri. - Kwik Trip, Inc. in Minnesota and Wisconsin and Kwik Star convenience stores in Iowa. The Somerset Refinery, Inc. at Somerset Oil stations in Kentucky. Aloha Petroleum - Tri-Par Oil Company - Turkey Hill Minit Markets - Texaco - Petro-Canada - Sunoco-Canada - Road Ranger located in Illinois, Indiana, Iowa, Kentucky, Missouri, Ohio and Wisconsin What is TOP TIER Detergent Gasoline? TOP TIER Detergent Gasoline is a new class of gasoline with enhanced detergency. It meets new, voluntary deposit control standards developed by six automotive companies that exceed the detergent requirements imposed by the EPA. Where Can TOP TIER Detergent Gasoline Be Purchased? The TOP TIER program began on May 3, 2004 and many fuel marketers have joined the program and have introduced TOP TIER Detergent Gasoline. This is a voluntary program and not all fuel marketers will offer this product. Once fuel marketers make public announcements, they will appear on a list of brands that meet the TOP TIER standards. Where Can I find the Latest Information on TOP TIER Fuel and Retailers? On the web, please visit www.toptiergas.com for additional information and updated retailer lists. Who developed TOP TIER Detergent Gasoline standards? TOP TIER Detergent Gasoline standards were developed by six automotive companies: Audi, BMW, General Motors, Honda, Toyota and Volkswagen. Why was TOP TIER Detergent Gasoline developed? TOP TIER Detergent Gasoline was developed to increase the level of detergent additive in gasoline. The EPA requires that all gasoline sold in the U.S. contain a detergent additive. However, the requirement is minimal and in many cases, is not sufficient to keep engines clean. In order to meet TOP TIER Detergent Gasoline standards, a higher level of detergent is needed than what is required by the EPA. Also, TOP TIER was developed to give fuel marketers the opportunity to differentiate their product. Why did the six automotive companies join together to develop TOP TIER? All six corporations recognized the benefits to both the vehicle and the consumer. Also, joining together emphasized that low detergency is an issue of concern to several automotive companies. What are the benefits of TOP TIER Detergent Gasoline? TOP TIER Detergent Gasoline will help keep engines cleaner than gasoline containing the "Lowest Additive Concentration" set by the EPA. Clean engines help provide optimal fuel economy and performance and reduced emissions. Also, use of TOP TIER Detergent Gasoline will help reduce deposit related concerns. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Fuel System - TOP TIER Detergent Gasoline (Canada) > Page 5037 Fuel: Technical Service Bulletins Fuel - Top Tier Detergent Gasoline Information Bulletin No.: 04-06-00-047 Date: June 24, 2004 ADVANCED SERVICE INFORMATION Subject: Top Tier Detergent Gasoline (Deposits, Fuel Economy, No Start, Power, Performance, Stall Concerns) Models: 2005 and Prior All General Motors Passenger Cars and Trucks (U.S. Only) A new class of gasoline, called Top Tier Detergent Gasoline, will be appearing at retail stations of some fuel marketers. This gasoline meets detergency standards developed by four automotive companies. A description of the concept and benefits of Top Tier is provided in the following question and answer section. What is Top Tier Detergent Gasoline? Top Tier Detergent Gasoline is a new class of gasoline with enhanced detergency. It meets new, voluntary deposit control standards developed by four automotive companies that exceed the detergent requirements imposed by the EPA. Who developed Top Tier Detergent Gasoline standards? Top Tier Detergent Gasoline standards were developed by four automotive companies: BMW, General Motors, Honda and Toyota. Why was Top Tier Detergent Gasoline developed? Top Tier Detergent Gasoline was developed to increase the level of detergent additive in gasoline. The EPA requires that all gasoline sold in the U.S. contain a detergent additive. However, the requirement is minimal and in many cases, is not sufficient to keep engines clean. In order to meet Top Tier Detergent Gasoline standards, a higher level of detergent is needed than what is required by the EPA. Also, Top Tier was developed to give fuel marketers the opportunity to differentiate their product. Why did the four automotive companies join together to develop Top Tier? All four corporations recognized the benefits to both the vehicle and the consumer. Also, joining together emphasized that low detergency is an issue of concern to several automotive companies. What are the benefits of Top Tier Detergent Gasoline? Top Tier Detergent Gasoline will help keep engines cleaner than gasoline containing the "Lowest Additive Concentration" set by the EPA. Clean engines help provide optimal fuel economy and performance and reduced emissions. Also, use of Top Tier Detergent Gasoline will help reduce deposit related concerns. Who should use Top Tier Detergent Gasoline? All vehicles will benefit from using Top Tier Detergent Gasoline over gasoline containing the "Lowest Additive Concentration" set by the EPA. Those vehicles that have experienced deposit related concerns may especially benefit from use of Top Tier Detergent Gasoline. Where can Top Tier Detergent Gasoline be purchased? The Top Tier program began on May 3, 2004. Some fuel marketers have already joined and are making plans to introduce Top Tier Detergent Gasoline. This is a voluntary program and not all fuel marketers will offer this product. Once fuel marketers make public announcements, a list of all fuel marketers meeting Top Tier standards will be made available. For now, look for the "Top Tier" designation at the gas pump. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Fuel System - TOP TIER Detergent Gasoline (Canada) > Page 5038 Fuel: Technical Service Bulletins Fuel - Reformulated/Oxygenated Gasolines FILE IN SECTION: 0 - General Information BULLETIN NO.: 57-01-02 DATE: June, 1995 SUBJECT: Reformulated Gasoline (RFG), Oxygenated Gasoline and California Phase 2 RFG MODELS: 1995 and Prior Passenger Cars and Trucks General Motors customers will be potentially exposed to a variety of different fuel types. Besides the conventional gasoline available, new types such as Reformulated Gasoline (RFG), oxygenated gasoline, and starting in 1996, California Phase 2 RFG. Reformulated Gasoline (RFG) is blended to burn more cleanly and not to evaporate as readily. RFG must contain a minimum of 2 percent oxygen, which is usually achieved with ethanol or EPA-approved ethers such as methyl tertiary-butyl ether (MTBE). This type of fuel is required by the Clean Air Act in the nine worst ozone non-attainment areas of the country, and may also be required in other areas designated ozone non-attainment, at the option of the states. RFG is intended to produce approximately 15 percent less pollution than conventional gasoline. Using RFG should reduce the total health risk to the public by reducing exposure to ozone and air toxins. General Motors supports the use of RFG as a cost effective means of providing air quality benefits. Oxygenated gasolines are prevalent in the wintertime for Carbon Monoxide (CO) non-attainment areas. These fuels contain oxygen components similar to RFG. Approximately 50 percent of the fuel sold in the U.S. in the wintertime contains an oxygenate component. Vehicle fuel economy may be slightly reduced, if at all, by the use of gasoline containing oxygenates. Fuel economy is most affected by engine and vehicle type, driving habits, weather conditions, and vehicle maintenance. Properly blended RFG, oxygenated gasoline, and California Phase 2 RFG will have no adverse effect on vehicle performance or to the durability of engine and fuel system components. In fact, the General Motors Owner's Manual fuel statements have consistently permitted the use of properly blended fuels containing up to 10 percent ethanol (since 1980) and up to 15 percent methyl tertiary-butyl ether (MTBE) for current and all past model year vehicles. These statements continue to be valid. The use of oxygenate-containing fuels will not invalidate the GM vehicle warranty. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel > Component Information > Technical Service Bulletins > Page 5039 Fuel: Specifications FUEL SPECIFICATIONS The fuel must meet ASTM Standard: D4814 (U.S.). OCTANE REQUIREMENTS Minimum octane recommended: 87 {(R+M)/2} octane where R = research octane number and M = motor octane number. GASOLINE WITH ALCOHOL NOTICE: Do not spill fuel containing alcohol on the vehicle. Alcohol can cause damage to the paint finish and trim. Methyl Tertiary-Butyl Ether (MTBE) Fuel containing Methyl Tertiary-butyl Ether (MTBE) may be used, providing there is no more than 15% alcohol by volume. Ethanol Fuel containing ethanol (ethyl) or grain alcohol may be used, providing there is no more than 10% ethanol alcohol by volume. Methanol Fuel containing methanol (methyl) or wood alcohol may be used, providing there is no more than 5% methanol by volume. Use of fuel (gasohol) that contains more than 5% methanol can corrode metal fuel system components and damage plastic and rubber parts. NOTICE: Do not use fuel that contains more than 5% methanol. Use of a fuel (gasohol) that contains more than 5% of methanol can corrode metal fuel system components and damage plastic and rubber parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Filler Cap > Component Information > Locations Filler Pipe And Cap Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Filler Cap > Component Information > Locations > Page 5043 Fuel Filler Cap: Description and Operation Filler Pipe And Cap The fuel tank filler pipe is equipped with a threaded-type cap. The threaded part of the cap requires several turns counterclockwise to remove. A built-in torque-limiting device prevents over tightening. To install, turn the cap clockwise until a clicking noise is heard. This signals that the correct torque has been reached and the cap is fully seated. NOTICE: If a fuel filler cap requires replacement, use only a cap with the same features. Failure to use the correct cap can result in a serious malfunction of the system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Filter > Fuel Pressure Release > System Information > Service and Repair Fuel Pressure Release: Service and Repair WARNING: - To reduce the risk of fire and personal injury, it is necessary to relieve the fuel system pressure before servicing fuel system components. - After relieving the fuel system pressure a small amount of fuel may be released when servicing fuel lines or connections. In order to reduce the chance of personal injury, cover fuel line fittings with a shop towel before disconnecting, to catch any fuel that may leak out. Place the shop towel in an approved container when the disconnect is complete. Fuel Pressure Test Port PROCEDURE: 1. Disconnect the negative battery cable to avoid possible fuel discharge if an accidental attempt is made to start the engine. 2. Loosen the fuel filler cap to relieve tank pressure. 3. Connect the J 34730-1 fuel pressure gauge to the fuel pressure connection on the fuel rail. Wrap a shop towel around the fitting while connecting the gauge to avoid spillage. 4. Install a bleed hose into an approved container and open the valve slowly to relieve system pressure. Fuel connections are now safe for servicing. 5. Drain any fuel remaining in the gauge into an approved container. NOTE: After repairs are complete, tighten the fuel cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Technical Service Bulletins > Fuel System - Fuel Injector Maintenance Cleaning Fuel Injector: Technical Service Bulletins Fuel System - Fuel Injector Maintenance Cleaning Bulletin No.: 04-06-04-051B Date: January 04, 2006 INFORMATION Subject: Maintenance Cleaning of Fuel Injectors Models: 2006 and Prior All General Motors Passenger Cars and Trucks 2003-2006 HUMMER H2 2006 HUMMER H3 Supercede: This bulletin is being revised to add models and model years and update the name and part number of GM Fuel System Treatment. Please discard Corporate Bulletin Number 04-06-04-051A (Section 06 - Engine/Propulsion System). General Motors is aware that some companies are marketing tools, equipment and programs to support fuel injector cleaning as a preventative maintenance procedure. General Motors does not endorse, support or acknowledge the need for fuel injector cleaning as a preventative maintenance procedure. Fuel injector cleaning is approved only when performed as directed by a published GM driveability or DTC diagnostic service procedure. Due to variation in fuel quality in different areas of the country, the only preventative maintenance currently endorsed by GM regarding its gasoline engine fuel systems is the addition of GM Fuel System Treatment PLUS, P/N 88861011 (for U.S. ACDelco(R), use P/N 88861013) (in Canada, P/N 88861012), added to a tank of fuel at each oil change. Refer to Corporate Bulletin Number 03-06-04-030A for proper cleaning instructions. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Technical Service Bulletins > Fuel System - Fuel Injector Maintenance Cleaning > Page 5052 Fuel Injector: Technical Service Bulletins Tools - Introduction Of The Fuel Injector Tester NO.: 93-I-39 DATE: June, 1993 GROUP: 6 CORP. NO.: 316501R SUBJECT: INFORMATION ON THE INTRODUCTION OF THE FUEL INJECTOR TESTER TOOL J - 39021 This bulletin is being revised to add information about the coil test and a list of driveability problems. In February, 1993, Kent-Moore shipped a new Fuel Injector Tester, tool J-39021, as part of the Essential Tool Program. This tool has the capability of performing injector balance and coil tests on all GM and many non-GM fuel injection systems. The injector balance test is one familiar to most technicians where fuel pressure drop is measured as an injector is energized for a set period of time. This fuel pressure drop is compared to that of the other injectors in the vehicle or a published standard. The injector coil test is a new test whereby the injector's resistance is measured during normal gperation by feeding a fixed current through the injector and measuring the voltage across the injector. Injector coil failures are more accurately detected using this method than by simply measuring the injectors resistance with an ohmmeter. Refer to the instructions included with the tool for testing procedures. This tool, and the injector coil test specifically, were developed to detect deterioration of injector coils due to the introduction of injector cleaners and fuel blends containing high levels of alcohol. Alcohol and water carried by the alcohol may attack and corrode injector coils resulting in a change in coil resistance and one or more of the following driveability symptoms: ^ rough idle ^ engine miss/surge ^ stall after start/hard start ^ fails emission test ^ poor fuel economy ^ exhaust odor The injector coil test procedure also requires the use of the Digital Voltmeter, J-39200, to measure the voltage across the injector during the test. The Fuel Injector Tester, J-39021, supplies one of three fixed current values throughout the duration of the test. Selection of the supply current value (0.5, 2.5, or 4.0 amps) is based on the injector's specified resistance. When the push-to-start-test button is pressed, the tool energizes the injector coil for five seconds. The condition of the injector coil (pass/fail) is determined by the voltage reading displayed on the voltmeter while the injector is energized. Instructions and specifications for most GM fuel injectors are included with the tool. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Technical Service Bulletins > Page 5053 Fuel Injector: Specifications Injector Resistence .............................................................................................................................. ........................................................ 11.8 - 12.6 ohms At 68 degrees F Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Technical Service Bulletins > Page 5054 Fuel Injector: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Technical Service Bulletins > Page 5055 Engine Left Side Upper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions Fuel Injector: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5058 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5059 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5060 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5061 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5062 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5063 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5064 Fuel Injector: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5065 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5066 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5067 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5068 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5069 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5070 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5071 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5072 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5073 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5074 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5075 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5076 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5077 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5078 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5079 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5080 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5081 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5082 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5083 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5084 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5085 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5086 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5087 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Diagram Information and Instructions > Page 5088 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Page 5089 Fuel Injector: Application and ID Fuel Injector Id When ordering new fuel injectors, be sure to order the correct injector for the application being serviced. The upper and lower fuel injector O-rings use different part numbers. To identify the correct 0-ring, the upper 0-ring is black and the lower 0-ring is brown. Both are the same size but are made of different material. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Page 5090 Fuel Injector: Description and Operation Fuel Injector The top-feed fuel injector assembly is a solenoid operated device, controlled by the Powertrain Control Module (PCM), that meters pressurized fuel to a single engine cylinder. The PCM energizes the injector solenoid. which opens a ball valve, allowing fuel to flow past the ball valve, and through a recessed flow director plate. The director plate has six machined holes that control the fuel flow, generating a conical spray pattern of finely atomized fuel at the injector tip. Fuel is directed at the intake valve, causing it to become further atomized and vaporized before entering the combustion chamber. An injector that is stuck partly open would cause loss of pressure after engine shutdown. Consequently, long cranking times would be noticed on some engines. Dieseling could also occur, because some fuel could be delivered to the engine after the ignition is turned "OFF". Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Page 5091 Fuel Injector: Testing and Inspection Most GM manufacturers now use a voltage drop and/or a fuel pressure drop test to measure Fuel Injector Coil Integrity. These test sequences can be found in Computers and Control Systems, under A, C or System Diagnostic Charts. See: Computers and Control Systems/Testing and Inspection Within these tests you might find an "Ohm" reading of the Injector, but generally this measurement is No Longer Used to solely determine the Pass/Fail quality of the Injector coil. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Injector > Component Information > Diagrams > Page 5092 Fuel Injector: Service and Repair Fuel Injector and Clip CAUTION: Use care in removing the fuel injectors to prevent damage to the electrical connector pins on the injector and the nozzle. The fuel injector is serviced as a complete assembly only. The fuel injector is an electrical component and should not be immersed in any type of cleaner. If fuel injectors are found to be leaking, the engine oil may be contaminated with fuel. REMOVE OR DISCONNECT 1. Disconnect negative battery cable. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery / Service and Repair. 3. Remove Fuel Rail assembly. ^ Refer to Fuel Rail / Service and Repair. DISASSEMBLE 1. Spread injector clip to release injector from fuel rail. 2. Fuel injector assembly. 3. Discard injector retainer clip. 3. Injector O-ring seals from both ends of injector and discard. Save O-Ring backup for use in reinstallation. NOTICE: ^ Refer to Application and ID to insure ordering correct replacement parts. ^ When replacing injector 0-rings, be sure to install the brown 0-ring in the lower position. ^ The fuel injector lower O-ring uses a nylon collar, called the O-ring backup, to properly position the O-ring on the injector. Be sure to reinstall the O-ring backup, or the sealing O-ring may move on the injector when installing the fuel rail and result in a possible vacuum leak. ASSEMBLE 1. Lubricate new injector O-ring seals with clean engine oil, and install on injector. 2. New retainer clip onto injector. 3. Fit injector into fuel rail injector socket, with electrical connector facing outward. 4. Push injector into socket until retainer clip locks onto flange on fuel rail. INSTALL OR CONNECT 1. Install fuel rail assembly. 2. Tighten fuel filler cap 3. Connect negative battery cable INSPECT ^ Turn ignition switch to "ON" position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Regulator > Component Information > Specifications Fuel Pressure Regulator: Specifications Fuel Pressure Regulator Attaching Screw ................................................................................................................................................... 10 Nm (89 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Regulator > Component Information > Specifications > Page 5096 Fuel Pressure Regulator: Locations Fuel Rail Assembly. The fuel pressure regulator is bolted to the fuel rail assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Regulator > Component Information > Specifications > Page 5097 Fuel Pressure Regulator: Description and Operation Pressure Regulator The fuel pressure regulator is a diaphragm-operated relief valve with fuel pump pressure on one side, and regulator spring pressure and intake manifold vacuum on the other. The regulator's function is to maintain a constant pressure differential across the injectors at all times. The pressure regulator compensates for engine load by increasing fuel pressure as engine vacuum drops. With the ignition "ON" and engine "OFF" (zero vacuum), system fuel pressure at the pressure test connection should be 284 - 325 kPa (41 - 47 psi). If the pressure is too low, poor performance could result. If the pressure is too high excessive odor and a Diagnostic Trouble Code (DTC) 45/65 may result. CHART A-7 has information on diagnosing fuel pressure conditions. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Regulator > Component Information > Specifications > Page 5098 Fuel Pressure Regulator: Service and Repair Fuel Rail Assembly. Fuel Pressure Regulator Assembly. NOTICE: Fuel pressure Regulator is serviced as a complete assembly only. REMOVE OR DISCONNECT 1. Disconnect negative battery terminal. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery / Service and Repair. 3. Remove fuel rail assembly. ^ Refer to Fuel Rail / Service and Repair. DISASSEMBLE 1. Remove fuel tube bracket attaching screw and bracket. 2. Remove pressure regulator attaching screw. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Regulator > Component Information > Specifications > Page 5099 3. Remove pressure regulator from fuel rail. 4. Remove fuel outlet tube retainer clip and fuel outlet tube from pressure regulator. 6. Remove fuel regulator inlet O-ring and discard. 6. Remove fuel outlet tube O-ring and discard. INSPECT ^ Filter screen for contamination. Remove and discard if dirty. ASSEMBLE 1. Lubricate new pressure regulator inlet O-ring with clean engine oil and install on regulator. 2. Lubricate new fuel outlet tube O-ring with clean engine oil and install on on fuel outlet tube. 3. Install fuel outlet tube into regulator and install retainer clip. 4. Push regulator into rail 5. Pressure regulator attaching screw. Thread-Locking Material The hardware used to attach the pressure regulator is coated with thread-locking adhesive. If the pressure regulator are removed for service, inspect the attaching screw threads. There should he enough thread-locking material (adhesive or compound) on the threads to insure proper relocking. If not, clean the threads and apply Loctite 262 to the threads before re-assembly Replacement screws are included in the service screw assortment package. New attaching hardware is included in the service packages. Tighten ^ Pressure regulator attaching screw to 10 Nm (89 lb in.). 6. Fuel tube bracket and attaching screw. Tighten ^ Pressure regulator attaching screw to 5 Nm (44 lb in.). INSTALL OR CONNECT 1. Fuel rail assembly. 2. Tighten fuel filler cap. 3. Connect negative battery cable. INSPECT ^ Turn ignition switch to "ON" position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Test Port > Component Information > Locations Fuel Pressure Test Port Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pressure Test Port > Component Information > Locations > Page 5103 Fuel Pressure Test Port: Service and Repair Fuel Test Port Valve CLEAN ^ Area around fuel pressure connection with GM X-3OA or equivalent. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery System / Service and Repair. 3. Fuel pressure connection valve assembly. INSTALL OR CONNECT 1. Fuel pressure connection valve assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ Turn ignition switch to the "ON" position for two seconds, then turn to the "OFF" position for ten seconds. Again turn to "ON" position, and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pressure > Diagnostic Connector - Fuel Pump > Component Information > Locations Diagnostic Connector - Fuel Pump: Locations The fuel pump test connector is located in the engine compartment near the A/C accumulator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations Fuel Pressure Test Port Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pressure > Fuel Pressure Test Port > Component Information > Locations > Page 5112 Fuel Pressure Test Port: Service and Repair Fuel Test Port Valve CLEAN ^ Area around fuel pressure connection with GM X-3OA or equivalent. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to Fuel Delivery System / Service and Repair. 3. Fuel pressure connection valve assembly. INSTALL OR CONNECT 1. Fuel pressure connection valve assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ Turn ignition switch to the "ON" position for two seconds, then turn to the "OFF" position for ten seconds. Again turn to "ON" position, and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Locations Fuel Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions Fuel Pump Relay: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5118 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5119 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5120 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5121 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5122 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5123 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5124 Fuel Pump Relay: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5125 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5126 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5127 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5128 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5129 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5130 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5131 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5132 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5133 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5134 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5135 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5136 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5137 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5138 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5139 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5140 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5141 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5142 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5143 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5144 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5145 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5146 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5147 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5148 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Page 5149 Fuel Pump Relay: Description and Operation When the ignition switch is turned to the "ON" position (before engaging starter), the energizes the fuel pump relay for two seconds causing the fuel pump to pressurize the fuel system. If the Powertrain Control Module (PCM) does not receive ignition reference pulses (engine cranking or running) within two seconds, it shuts "OFF" the fuel pump relay, causing the fuel pump to stop. As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Pump > Fuel Pump Relay > Component Information > Diagrams > Page 5150 Fuel Pump Relay: Service and Repair Fuel Pump (Circuit Opening) Relay REMOVE OR DISCONNECT 1. Underhood (U/H) electrical center cover. 2. Fuel pump relay. INSTALL OR CONNECT 1. Fuel pump relay. 2. Underhood (U/H) electrical center cover. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Specifications Fuel Rail: Specifications Fuel Crossover Tube Screws .............................................................................................................. ........................................................... 5 Nm (44 lb in.) Fuel Pressure Regulator Screw ........................................................................................................... ......................................................... 10 Nm (89 lb in.) Fuel Rail and Resonator Bracket Bolts ........................................................................................................................................................ 10 Nm (89 lb in.) Fuel Tube Bracket Attaching Screw .............................................................................................................................................................. 5 Nm (44 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Specifications > Page 5154 Fuel Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Specifications > Page 5155 Fuel Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Specifications > Page 5156 Fuel Rail: Application and ID Fuel Rail Identification An eight digit identification number is stamped on the fuel rail assembly. Refer to this model identification number if servicing or part replacement is required. Names of component parts will be found on the numbered list that accompanies the disassembled view in Fuel Rail / Diagrams. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Specifications > Page 5157 Fuel Rail: Description and Operation Fuel Rail The fuel rail assembly is mounted to the engine intake manifold and performs several functions; it positions the injectors in the intake manifold, it distributes fuel evenly to the injectors, and it integrates the fuel pressure regulator into the fuel metering system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Service and Repair > Fuel Rail X-Over Tube Fuel Rail: Service and Repair Fuel Rail X-Over Tube Fuel X-Over Tube REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to the Fuel Delivery System / Service and Repair. 3. Fuel rail assembly. ^ Refer to Fuel Rail / Service and Repair. DISASSEMBLE 1. Fuel tube bracket attaching screw and bracket. 2. Crossover tube retainer attaching screws. 3. Crossover tube assembly from fuel rails. 4. 0-rings from crossover tube assembly and discard. ASSEMBLE 1. Lubricate new crossover tube assembly 0-rings with clean engine oil and install on crossover tube. 2. Crossover tube assembly into fuel rail sections. 3. Crossover tube retainer attaching screws. Tighten ^ Crossover tube retainer attaching screws to 5 Nm (44 lb in.). 4. Fuel tube bracket and attaching screw. Tighten ^ Fuel tube bracket attaching screw to 5 Nm (44 lb in.). INSTALL OR CONNECT 1. Fuel rail assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ turn ignition switch to "ON" position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Service and Repair > Fuel Rail X-Over Tube > Page 5160 Fuel Rail: Service and Repair Fuel Outlet Tube Fuel Outlet Tube REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to the Fuel Delivery System / Service and Repair. 3. Fuel rail assembly. ^ Refer to Fuel Rail / Service and Repair. DISASSEMBLE 1. Fuel tube bracket and attaching screw. 2. Fuel outlet tube retainer clip. 3. Fuel outlet tube from pressure regulator. 4. 0-ring from outlet tube and discard. ASSEMBLE 1. Lubricate new 0-ring with clean engine oil and install on fuel outlet tube. 2. Push fuel outlet tube into fuel pressure regulator. 3. Fuel outlet tube retainer clip. 4. Fuel tube bracket and attaching screw. Tighten ^ Fuel tube bracket attaching screw to 5 Nm (44 lb in.). INSTALL OR CONNECT 1. Fuel rail assembly. 2. Tighten fuel filler cap. 3. Negative battery cable. INSPECT ^ Turn ignition switch to "0N" position for two seconds, then turn "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Service and Repair > Fuel Rail X-Over Tube > Page 5161 Fuel Rail: Service and Repair Fuel Rail Replacement NOTICE ^ Use care in removing the fuel rail assembly to prevent damage to the injector electrical connector terminals and the injector spray tips. When removed, support the rail to avoid damaging its components. ^ Prevent dirt and other contaminates from entering open lines and passages. Fittings should be capped, and holes plugged, during servicing. ^ The upper and lower 0-rings are different colors (black and brown). Be sure to install the black 0-ring in the upper position and the brown 0-ring in the lower position on the injector. The 0-rings are the same size but are made of different materials. CLEAN ^ Before removal, the fuel rail assembly may be cleaned with a spray type engine cleaner, GM X-30A or equivalent, following package instructions. Do Not soak fuel rails in liquid cleaning solvent. Fuel Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Service and Repair > Fuel Rail X-Over Tube > Page 5162 Fuel Rail REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. ^ Refer to the Fuel Delivery System / Service and Repair. 3. Resonator. 4. Quick-connect fittings at engine fuel pipes: A. Slide rubber dust covers from quick-connect fittings at engine fuel pipes. B. Grasp both sides of fitting. Twist female connector 1/4 turn in each direction to loosen any dirt within fining. WARNING: Safety glasses must be worn when using compressed air, as flying dirt particles may cause eye injury. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Rail > Component Information > Service and Repair > Fuel Rail X-Over Tube > Page 5163 C. Using compressed air, blow dirt out of fitting. D. Choose correct tool from J 37088-A tool set for size of fitting. Insert tool into female connector, then push/pull inward to release locking tabs. E. Pull connection apart. CLEAN AND INSPECT NOTICE: If it is necessary to remove rust or burrs from fuel pipe, use emery cloth in a radial motion with the pipe end to prevent damage to O-ring sealing surface. ^ Using a clean shop towel, wipe off male pipe end. ^ Inspect both ends of fitting for dirt and burrs. Clean or replace component assemblies as required. 5. Vacuum lines at pressure regulator and Emissions Vapor (EVAP) canister purge solenoid. 6. Electrical harness and cables from routing clips on resonator bracket. 7. Resonator bracket. 8. Injector electrical connectors. ^ Identify connectors to their corresponding injectors to assure correct sequential injector firing order after reassembly. 9. Fuel rail assembly. DISASSEMBLE ^ Injector lower 0-ring seal (Brown) from spray tip end of each injector. Discard 0-ring seals. Save 0-ring backups. ^ The fuel injector lower 0-ring uses a nylon collar, called the 0-ring backup, to properly position the 0-ring on the injector. Be sure to reinstall the 0-ring backup, or the sealing 0-ring may move on the injector when installing the fuel rail and result in a possible vacuum leak and driveability complaints will occur. ASSEMBLE ^ Lubricate new lower injector 0-ring seals (brown) and install on spray tip end of each injector. INSTALL OR CONNECT 1. Fuel rail assembly to intake manifold. 2. Resonator bracket. Tighten ^ Fuel rail and resonator attaching bolts to 10 Nm (89 lb in.). 3. Injector electrical connectors. ^ Make sure that each connector is installed on the proper injector to assure correct sequential injector firing order. ^ Rotate injector(s) as required to avoid stretching wire harness. 4. Electrical harness and cables into routing clips on resonator bracket. 5. Vacuum lines to EVAP canister purge solenoid and fuel pressure regulator. 6. Quick-connect fittings to engine fuel pipes: A. Apply a few drops of clean engine oil to the male ends of the engine fuel rail inlet and outlet tubes. B. Push both sides of fitting together to cause the retaining tabs/fingers to snap into place. C. Once installed, pull on both sides of fitting to make sure connection is secure. D. Slide dust covers over quick-connect fittings. 7. Tighten fuel filler cap. 8. Negative battery cable. Inspect ^ Turn ignition switch to "0N" position for two seconds, then turn "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. 9. Resonator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Return Line > Component Information > Locations Fuel Return Line: Locations Supply And Return Line Replacement The fuel supply and return lines are routed along the left frame rail under the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Return Line > Component Information > Description and Operation > Nylon Fuel Pipes Fuel Return Line: Description and Operation Nylon Fuel Pipes Nylon fuel pipes are designed to perform the same job as the steel or flexible fuel pipes or hoses they replace. Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There are two sizes used: 3/8" ID for the fuel feed, and 5/16" ID for the fuel return. The fuel feed and return pipes are assembled as a harness. Retaining clips hold the pipes together and provide a means for attaching the pipes to the vehicle. Sections of the pipes that are exposed to chafing, high temperature or vibration are protected with heat resistant rubber hose and/or corrugated plastic conduit. Nylon fuel pipes are somewhat flexible and can be formed around gradual turns under the vehicle. However, if forced into sharp bends, nylon pipes will kink and restrict fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Some special care should be taken when working on a vehicle with nylon fuel pipes. WARNING: To Reduce the Risk of Fire and Personal Injury: ^ Always cover nylon fuel pipes with a wet towel before using a torch near them. Also, never expose the vehicle to temperatures higher then 115° C (239° F) for more than one hour, or more than 90° C (194° F) for any extended period. ^ Take care not to nick or scratch the nylon fuel pipes. If damaged, they must be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Return Line > Component Information > Description and Operation > Nylon Fuel Pipes > Page 5169 Fuel Return Line: Description and Operation Quick-Connect Fittings Quick-connect type fittings provide a simplified means of installing and connecting fuel system components. There are two types of quick-connect fittings used at different locations in the fuel system. Each type consists of a unique female socket and a compatible male connector. O-rings, located inside the female socket, provide the fuel seal. Integral locking tabs or fingers hold the fittings together. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Return Line > Component Information > Description and Operation > Page 5170 Fuel Return Line: Service and Repair Supply And Return Line Replacement TOOLS REQUIRED J 37088-A, Fuel Line Separator Tool Set. NOTICE: ^ If nylon fuel feed or return pipes becomes kinked, and cannot be straightened, they must be replaced. ^ Do Not attempt to repair sections of nylon fuel pipes. If damaged, replace. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. Refer to Fuel Delivery / Service and Repair. 3. Quick-connect fittings at fuel rail in engine compartment. 4. Fuel feed and return pipe retaining clip at brake booster. 5. Raise vehicle. 6. Quick-connect fittings at fuel filter. 7. Lower fuel tank shield attaching screws and lower fuel tank shields. 8. Fuel feed, return, and EVAP pipe underbody retainer. 9. Quick-connect fittings at fuel sender assembly. 10. Fuel feed and return pipe retaining clips and fuel feed and return pipes. ^ Note position of fuel pipes for installation. INSTALL OR CONNECT WARNING: To Reduce the Risk of Fire and Personal Injury: ^ If nylon fuel pipes are nicked, scratched or damaged during installation, they must be replaced. ^ When installing new fuel pipes, Do NOT hammer directly on the fuel harness body clips as this may damage the nylon pipes resulting in a possible fuel leak. 1. Lower vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Return Line > Component Information > Description and Operation > Page 5171 2. Rear ends of fuel feed and return pipes into top forward frame hole. 3. Raise vehicle. 4. Route pipes in same position as noted during disassembly. 5. Quick-connect fittings at fuel sender assembly. 6. Fuel feed, return, and EVAP pipe underbody retainer. 7. Lower fuel tank shields and tank shield attaching screws. Tighten Lower fuel tank shield screws to 1 Nm (9 lb in.). 8. Quick-connect fittings at fuel filter. 9. Close all retaining clips. 10. Lower vehicle. 11. Fuel feed and return pipe retaining clip at brake booster. 12. Quick-connect fittings at fuel rail in engine compartment. 13. Negative battery cable. INSPECT ^ Turn ignition switch to "ON" position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Supply Line > Component Information > Locations Fuel Supply Line: Locations Supply And Return Line Replacement The fuel supply and return lines are routed along the left frame rail under the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Supply Line > Component Information > Description and Operation > Nylon Fuel Pipes Fuel Supply Line: Description and Operation Nylon Fuel Pipes Nylon fuel pipes are designed to perform the same job as the steel or flexible fuel pipes or hoses they replace. Nylon pipes are constructed to withstand maximum fuel system pressure, exposure to fuel additives, and changes in temperature. There are two sizes used: 3/8" ID for the fuel feed, and 5/16" ID for the fuel return. The fuel feed and return pipes are assembled as a harness. Retaining clips hold the pipes together and provide a means for attaching the pipes to the vehicle. Sections of the pipes that are exposed to chafing, high temperature or vibration are protected with heat resistant rubber hose and/or corrugated plastic conduit. Nylon fuel pipes are somewhat flexible and can be formed around gradual turns under the vehicle. However, if forced into sharp bends, nylon pipes will kink and restrict fuel flow. Also, once exposed to fuel, nylon pipes may become stiffer and are more likely to kink if bent too far. Some special care should be taken when working on a vehicle with nylon fuel pipes. WARNING: To Reduce the Risk of Fire and Personal Injury: ^ Always cover nylon fuel pipes with a wet towel before using a torch near them. Also, never expose the vehicle to temperatures higher then 115° C (239° F) for more than one hour, or more than 90° C (194° F) for any extended period. ^ Take care not to nick or scratch the nylon fuel pipes. If damaged, they must be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Supply Line > Component Information > Description and Operation > Nylon Fuel Pipes > Page 5177 Fuel Supply Line: Description and Operation Quick-Connect Fittings Quick-connect type fittings provide a simplified means of installing and connecting fuel system components. There are two types of quick-connect fittings used at different locations in the fuel system. Each type consists of a unique female socket and a compatible male connector. O-rings, located inside the female socket, provide the fuel seal. Integral locking tabs or fingers hold the fittings together. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Supply Line > Component Information > Description and Operation > Page 5178 Fuel Supply Line: Service and Repair Supply And Return Line Replacement TOOLS REQUIRED J 37088-A, Fuel Line Separator Tool Set. NOTICE: ^ If nylon fuel feed or return pipes becomes kinked, and cannot be straightened, they must be replaced. ^ Do Not attempt to repair sections of nylon fuel pipes. If damaged, replace. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. Refer to Fuel Delivery / Service and Repair. 3. Quick-connect fittings at fuel rail in engine compartment. 4. Fuel feed and return pipe retaining clip at brake booster. 5. Raise vehicle. 6. Quick-connect fittings at fuel filter. 7. Lower fuel tank shield attaching screws and lower fuel tank shields. 8. Fuel feed, return, and EVAP pipe underbody retainer. 9. Quick-connect fittings at fuel sender assembly. 10. Fuel feed and return pipe retaining clips and fuel feed and return pipes. ^ Note position of fuel pipes for installation. INSTALL OR CONNECT WARNING: To Reduce the Risk of Fire and Personal Injury: ^ If nylon fuel pipes are nicked, scratched or damaged during installation, they must be replaced. ^ When installing new fuel pipes, Do NOT hammer directly on the fuel harness body clips as this may damage the nylon pipes resulting in a possible fuel leak. 1. Lower vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Supply Line > Component Information > Description and Operation > Page 5179 2. Rear ends of fuel feed and return pipes into top forward frame hole. 3. Raise vehicle. 4. Route pipes in same position as noted during disassembly. 5. Quick-connect fittings at fuel sender assembly. 6. Fuel feed, return, and EVAP pipe underbody retainer. 7. Lower fuel tank shields and tank shield attaching screws. Tighten Lower fuel tank shield screws to 1 Nm (9 lb in.). 8. Quick-connect fittings at fuel filter. 9. Close all retaining clips. 10. Lower vehicle. 11. Fuel feed and return pipe retaining clip at brake booster. 12. Quick-connect fittings at fuel rail in engine compartment. 13. Negative battery cable. INSPECT ^ Turn ignition switch to "ON" position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank > Fuel Filler Pipe <--> [Fuel Filler Hose] > Component Information > Specifications Fuel Filler Pipe: Specifications Fuel Filler Pipe Attaching Screws ........................................................................................................ ......................................................... 6 Nm (53 lb in.) Fuel Filler Pipe Ground Strap Screw ............................................................................................................................................................. 4 Nm (35 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank > Fuel Filler Pipe <--> [Fuel Filler Hose] > Component Information > Specifications > Page 5184 Filler Pipe And Cap Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank > Fuel Filler Pipe <--> [Fuel Filler Hose] > Component Information > Specifications > Page 5185 Fuel Filler Pipe: Description and Operation Filler Pipe And Cap The fuel tank filler pipe outlet is positioned at the rear of the vehicle. To prevent refueling with leaded fuel the fuel filler pipe has a built-in restrictor and deflector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank > Fuel Gauge Sender > Component Information > Locations Fuel Gauge Sender: Locations Mounted on Fuel Tank, Part of Fuel Tank Unit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank > Fuel Gauge Sender > Component Information > Locations > Page 5189 Fuel Pump/Sender Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Specifications > Mechanical Specifications Fuel Tank Unit: Mechanical Specifications Fuel Sender Assembly Attaching Nuts .......................................................................................................................................................... 3 Nm (27 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Specifications > Mechanical Specifications > Page 5194 Fuel Tank Unit: Pressure, Vacuum and Temperature Specifications Fuel Pressure ...................................................................................................................................... ......................................... 284 - 325 kPa (41 - 47 psi) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Locations > Component Locations Fuel Tank Unit: Component Locations Fuel Sender Assembly Replacement Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Locations > Component Locations > Page 5197 Fuel Sender Assembly The fuel pump is located in the fuel tank as part of the fuel level sender assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Locations > Component Locations > Page 5198 Fuel Tank Unit: Connector Locations LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Locations > Component Locations > Page 5199 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Locations > Page 5200 Fuel Tank Unit: Description and Operation Fuel Sender Typical Rheostat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Locations > Page 5201 Fuel Sender FUEL TANK UNIT The fuel tank unit is located inside the fuel tank and is attached to the top of the fuel tank. The fuel Tank Unit consists of the following major components: a fuel sender, fuel pump, and a fuel pump strainer. Fuel Sender Assembly The fuel sender consists of the float, wire float arm, rheostat and roll-over valve. Fuel level is sensed by the position of the float and float arm which operate the 90 ohm rheostat. As the float position changes, the amount of current passing through the rheostat varies, thus changing the gage reading on the instrument panel. The roll-over valve is pressed into the evaporative emission (EVAP) pipe of the fuel sender and is not serviced separately. The roll-over valve prevents fuel from entering the evaporative emission canister if the vehicle rolls over by shutting "OFF" the EVAP pipe to the canister. Fuel Pump The fuel pump is an electric medium pressure twin turbine pump which is mounted to the fuel sender assembly inside the fuel tank. The fuel is pumped to the fuel rail assembly at a specified flow and pressure by the fuel pump. Excess fuel is returned to the fuel tank by the return pipe. The fuel pump delivers a constant flow of fuel to the engine even during low fuel conditions and aggressive vehicle maneuvers. The electric fuel pump operation is controlled by the Powertrain Control Module (PCM) through a fuel pump relay. Fuel Pump Strainer A woven plastic fuel pump strainer is attached to the lower end of the fuel pump in the fuel tank. The functions of the fuel pump strainer are to filter contaminants and to wick fuel. The life of the fuel pump strainer is generally considered to be that of the fuel pump. The fuel pump strainer is self-cleaning and normally requires no maintenance. Fuel stoppage at this point indicates that the fuel tank contains an abnormal amount of sediment or water. In which case the tank should be thoroughly cleaned. (See "Fuel System Cleaning.") If the fuel pump strainer is plugged, replace it with a new fuel pump strainer. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Service and Repair > Fuel Sender Assembly Replacement Fuel Tank Unit: Service and Repair Fuel Sender Assembly Replacement Fuel Sender Assembly Replacement Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Service and Repair > Fuel Sender Assembly Replacement > Page 5204 Fuel Sender Assembly REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. Refer to Fuel Delivery / Service and Repair. 3. Drain fuel tank. 4. Fuel tank assembly. 5. Fuel sender assembly attaching nuts, retaining flange, fuel sender assembly and O-ring from fuel tank. Discard O-ring. CLEAN ^ Fuel sender assembly sealing surfaces. INSTALL OR CONNECT NOTICE: ^ Care should be taken not to fold over or twist the fuel pump strainer when installing the fuel sender assembly as this will restrict fuel flow. Also, assure that the fuel pump strainer does not block full travel of float arm. 1. Position new 0-ring on fuel tank. 2. Fuel sender assembly, retaining flange and fuel sender assembly attaching nuts. Tighten Fuel sender assembly attaching nuts to 3 Nm (27 lb in.). 3. Fuel tank. 4. Add fuel and install fuel filler cap. 5. Negative battery cable. INSPECT ^ Turn ignition switch to "ON" position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Service and Repair > Fuel Sender Assembly Replacement > Page 5205 Fuel Tank Unit: Service and Repair Fuel Pump Replacement Fuel Sender Assembly Replacement Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Service and Repair > Fuel Sender Assembly Replacement > Page 5206 Fuel Sender Assembly REMOVE OR DISCONNECT 1. Negative battery cable. 2. Relieve fuel system pressure. Refer to Fuel Delivery / Service and Repair. 3. Drain fuel tank. 4. Remove fuel tank assembly. 5. Remove fuel tank unit. DISASSEMBLE 1. Note position of fuel pump strainer on fuel pump. 2. Support sender with one hand and grasp strainer with other hand. Rotate strainer in one direction and pull off of pump. Discard strainer after inspection. 3. Loosen clamp and remove connecting hose from fuel pump outlet 4. Remove terminal retainer. 5. Disconnect fuel pump electrical connector and electrical connector from bottom of sender cover. 6. Remove retainer clip from fuel return pipe. 7. Remove fuel pump and level sensor assembly and spring from fuel sender. 8. Remove housing cover from fuel pump housing. 9. Fuel pump. INSPECT AND REPLACE 1. Fuel pump strainer. If strainer is contaminated, it must be replaced and the fuel tank should be removed and cleaned. 2. Always install a new pump strainer when replacing the fuel pump. 3. Fuel pump inlet for dirt and debris. ASSEMBLE 1. Install fuel level sensor to fuel pump housing. 2. Install fuel pump and isolator into fuel pump housing. NOTICE: ^ Small hole in the housing cover aligns over the fuel level sensor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Fuel Tank Unit > Component Information > Service and Repair > Fuel Sender Assembly Replacement > Page 5207 3. Connect housing cover to fuel pump housing. 4. Slide fuel pump and fuel level sensor assembly and spring onto fuel return pipe. NOTICE: ^ Fuel pump and fuel level sensor assembly must be aligned directly under fuel sender cover. 5. Depress spring and install retainer. 6. Connect hose to outlet and tighten clamp so that 5-8 teeth are engaged. 7. Connect fuel pump electrical connector and electrical connector to bottom of sender cover. 8. Install terminal retainer. 9. Support sender with one hand and position new pump strainer on pump in same position as noted during disassembly. INSTALL OR CONNECT 1. Install fuel tank unit. 2. Install fuel tank assembly. 3. Add fuel and install filler cap. 2. Negative battery cable. INSPECT ^ Turn ignition switch to "ON" position for two seconds, then turn to "OFF" for ten seconds. Again turn to "ON" position and check for fuel leaks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Specifications Idle Air Control (IAC): Specifications Idle Air Control (IAC) Valve Screws ............................................................................................................................................................ 3 Nm (27 lb in.) IAC Valve/Coolant Cover Assembly Screws ............................................................................................................................................. 3.2 Nm (28 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Specifications > Page 5211 Idle Air Control (IAC): Locations Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Specifications > Page 5212 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions Idle Air Control (IAC): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5215 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5216 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5217 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5218 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5219 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5220 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5221 Idle Air Control (IAC): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5222 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5223 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5224 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5225 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5226 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5227 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5228 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5229 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5230 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5231 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5232 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5233 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5234 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5235 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5236 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5237 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5238 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5239 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5240 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5241 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5242 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5243 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5244 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5245 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5246 Idle Air Control (IAC) Valve Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Diagram Information and Instructions > Page 5247 Idle Air Control (IAC) Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Page 5248 Idle Air Control (IAC): Description and Operation Throttle Body IAC Valve Flow The purpose of the Idle Air Control (IAC) valve assembly is to control engine idle speed while preventing stalls do to changes in engine load. The IAC valve, mounted in the throttle body, controls a portion of the bypass air. An orifice located between the throttle valves also supplies a constant amount of bypass air. By moving a conical valve known as a pintle, IN, towards the seat (to decrease air flow) or OUT, away from the seat (to increase air flow) a controlled amount of air can be bypassed. If engine speed is too low, more air is bypassed to increase RPM. If engine speed is too high, less air is bypassed to decrease RPM. The Powertrain Control Module (PCM) moves the IAC valve in small steps, called counts. These can be measured and displayed by a scan tool which plugs into the Data Link Connector (DLC). During idle, the proper position of the IAC valve is calculated by the PCM, based on battery voltage, coolant temperature, engine load, and engine RPM. If the RPM drops below specification and the throttle valve is closed, the PCM senses a near stall condition and calculates a new valve position to prevent stalling. ^ Engine idle speed is a function of total air flow into the engine based on IAC valve pintle position + crankcase ventilation valve flow + throttle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Page 5249 valve opening + bypass orifice air flow + calibrated vacuum loss through accessories. ^ Controlled idle speed is programmed into the PCM, which determines the correct lAC valve pintle position to maintain the desired idle speed for all engine operating conditions and loads. ^ The minimum idle air rate is set at the factory with a stop screw. This setting allows enough air flow by the throttle valves to cause the IAC valve pintle to be positioned a calibrated number of steps (counts), from the seat, during controlled idle operation. ^ If the IAC valve is disconnected and reconnected with the engine running, the idle speed may be wrong. If this occurs, reset the IAC valve by depressing the accelerator pedal slightly, start and run engine for five seconds, then turn ignition "OFF" for ten seconds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Diagrams > Page 5250 Idle Air Control (IAC): Adjustments To reset Idle Air Control (IAC) valve. 1. Depress accelerator pedal slightly. 2. Start and run engine for 5 seconds. 3. Turn ignition "OFF" for 10 seconds. 4. Restart engine and check for proper idle operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure Idle Air Control (IAC): Service and Repair Idle Air Control (IAC) Reset Procedure 1. Depress the accelerator pedal slightly. 2. Start and run the engine for five seconds. 3. Turn the ignition "OFF" for ten seconds. 4. Restart the engine and check for proper idle operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 5253 Idle Air Control (IAC): Service and Repair Idle Air Control (IAC) Valve Replacement Throttle Body Exploded View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 5254 IAC Valve REMOVE OR DISCONNECT 1. Resonator. 2. Distributor ventilation vacuum line at air intake duct. 3. Electrical connector from Intake Air Temperature (IAT) sensor. 4. Air intake duct. 5. Electrical connector from Idle Air Control (IAC) valve. 6. IAC valve assembly attaching screws. 7. IAC valve assembly. CLEAN AND INSPECT ^ Clean IAC valve O-ring sealing surface, pintle valve seat and air passage. The IAC valve may be cleaned using GM cleaner 1052626 or GM X-66A. Use a shop towel or parts brush to remove heavy deposits. - Shiny spots on the pintle or seat are normal, and do not indicate misalignment or a bent pintle shaft. If air passage has heavy deposits, remove throttle body for complete cleaning. ^ Inspect IAC valve O-ring for cuts, cracks, or distortion. Replace if damaged. NOTICE: If installing a new IAC valve, be sure to replace with an identical part. IAC valve pintle shape and diameter are designed for specific application. MEASURE (IF INSTALLING A NEW IAC) ^ Distance between tip of IAC valve pintle and mounting surface. If greater than 28 mm (1.100 in), use finger pressure to slowly retract the pintle. The force required to retract the pintle of a NEW valve will not cause damage to the valve. INSTALL OR CONNECT 1. Lubricate IAC valve O-ring with clean engine oil. 2. IAC Valve assembly. 3. IAC valve attaching screws. Tighten ^ IAC attaching screws to 3 Nm (27 lb in.). 4. Electrical connector to IAC valve. 5. Air intake duct. 6. Electrical connector to IAT valve. 7. Distributor ventilation vacuum line at air intake duct. 8. Resonator. 9. Reset IAC valve pintle position. A. Depress accelerator slightly. B. Start engine and release accelerator pedal, run engine for 5 seconds. C. Turn engine "OFF" for 10 seconds. D. Restart engine and check for proper idle operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 5255 Idle Air Control (IAC): Service and Repair Idle Air Control/Coolant Cover Assembly Throttle Body Exploded View REMOVE OR DISCONNECT 2. Negative battery cable. 2. Throttle body from intake manifold. ^ Refer to Throttle Body / Service and Repair. DISASSEMBLE 1. Idle Air Control (IAC) valve. 2. IAC valve/coolant cover assembly screws. 3. IAC valve/coolant cover assembly and gasket. ^ Discard gasket Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Idle Air Control (IAC) <--> [Idle Speed/Throttle Actuator - Electronic] > Component Information > Service and Repair > Idle Air Control (IAC) Reset Procedure > Page 5256 CLEAN AND INSPECT 1. Clean gasket sealing surface. 2. Inspect gasket sealing surface for corrosion or damage that would cause a coolant leak. Replace cover assembly or throttle body if necessary. ASSEMBLE 1. Install new gasket and cover assembly. 2. IAC Valve / coolant cover assembly screws. Tighten ^ IAC Valve / coolant cover assembly screws to 3.2 Nm (28 lb in.). 3. If installing a new IAC valve, measure distance between pintle and mounting surface. If greater than 28mm, use finger pressure to slowly retract the pintle. INSTALL OR CONNECT 1. Install and tighten IAC valve attaching screws Tighten ^ IAC Valve assembly screws to 3 Nm (27 lb in.). 2. Install throttle body to intake manifold. 3. Negative battery cable. 4. Reset IAC valve pintle position. Refer to ADJUSTMENTS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Specifications Oil Pressure Switch (For Fuel Pump): Specifications Fuel Pump Switch and Engine Oil Pressure Sensor ................................................................................................................................... 12 Nm (106 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch > Page 5262 Oil Pressure Switch (For Fuel Pump): Locations Oil Pressure Sensor/Fuel Pump Switch Fuel Pump - Oil Pressure Switch The sensor is threaded into a TEE fitting at the rear of the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions Oil Pressure Switch (For Fuel Pump): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5265 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5266 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5267 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5268 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5269 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5270 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5271 Oil Pressure Switch (For Fuel Pump): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5272 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5273 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5274 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5275 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5276 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5277 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5278 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5279 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5280 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5281 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5282 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5283 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5284 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5285 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5286 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5287 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5288 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5289 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5290 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5291 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5292 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5293 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5294 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5295 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5296 Fuel Pump Switch/Engine Oil Pressure Gage Sensor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5297 Fuel Pump Relay Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 5298 Oil Pressure Switch (For Fuel Pump): Description and Operation Fuel Pump - Oil Pressure Switch As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 5299 Oil Pressure Switch (For Fuel Pump): Service and Repair Fuel Pump - Oil Pressure Switch REMOVE OR DISCONNECT 1. Disconnect electrical connector. 2. Fuel pump switch and oil pressure sensor. INSTALL OR CONNECT 1. Fuel pump switch and oil pressure sensor. 2. Tighten to 12 Nm (106 lb in.) 3. Electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Locations Fuel Pump Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions Fuel Pump Relay: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5306 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5307 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5308 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5309 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5310 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5311 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5312 Fuel Pump Relay: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5313 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5314 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5315 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5316 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5317 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5318 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5319 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5320 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5321 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5322 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5323 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5324 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5325 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5326 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5327 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5328 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5329 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5330 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5331 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5332 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5333 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5334 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5335 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Diagram Information and Instructions > Page 5336 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Page 5337 Fuel Pump Relay: Description and Operation When the ignition switch is turned to the "ON" position (before engaging starter), the energizes the fuel pump relay for two seconds causing the fuel pump to pressurize the fuel system. If the Powertrain Control Module (PCM) does not receive ignition reference pulses (engine cranking or running) within two seconds, it shuts "OFF" the fuel pump relay, causing the fuel pump to stop. As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Relays and Modules - Fuel Delivery and Air Induction > Fuel Pump Relay > Component Information > Diagrams > Page 5338 Fuel Pump Relay: Service and Repair Fuel Pump (Circuit Opening) Relay REMOVE OR DISCONNECT 1. Underhood (U/H) electrical center cover. 2. Fuel pump relay. INSTALL OR CONNECT 1. Fuel pump relay. 2. Underhood (U/H) electrical center cover. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Resonator, Intake Air > Component Information > Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Locations > Component Locations > Page 5347 Powertrain Control Module (PCM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions Air Flow Meter/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5350 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5351 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5352 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5353 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5354 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5355 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5356 Air Flow Meter/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5357 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5358 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5359 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5360 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5361 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5362 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5363 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5364 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5365 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5366 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5367 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5368 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5369 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5370 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5371 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5372 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5373 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5374 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5375 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5376 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5377 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5378 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5379 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5380 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5381 MAF Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 5382 Air Flow Meter/Sensor: Description and Operation The Mass Air Flow (MAF) sensor measures the amount of air that is ingested by a vehicles' engine. This information is required by the engine's Powertrain Control Module (PCM) to schedule fuel and maintain the desired air/fuel ratio. The MAF sensor used on this vehicle is a hot wire type and is used to measure air flow rate. The Mass Air Flow (MAF) output frequency is a function of the power required to keep the air flow sensing elements (hot wires) at a fixed temperature above ambient temperature. As air flows through the MAF sensor the "hot wires" are cooled. The amount of cooling is proportional to the rate of air flow. As air flow increases a greater amount of current is required to maintain the "hot wires" at a constant temperature. The MAF sensor converts the changes in current draw to a frequency signal read by the PCM. The PCM calculates air flow (grams per second) based on this signal. A failure in the MAF circuit should set a Diagnostic Trouble Code (DTC) 48. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Air Flow Meter/Sensor > Component Information > Diagrams > Page 5383 Air Flow Meter/Sensor: Service and Repair Mass Air Flow Removal CAUTION: Take care when handling the Mass Air Flow (MAF). Do not dent, puncture, or otherwise damage the Honeycell located at the air inlet end of the MAF. Do not touch the sensing elements or allow anything (including cleaning solvents and lubricants) to come in contact with them. A small amount of GM lubricant (P/N = 99855406) may be used on the air duct only, to aid in installation. Do not drop or roughly handle the MAF. REMOVE OR DISCONNECT 1. Negative battery cable. 2. Electrical connector. 3. Carefully loosen air duct clamps and remove MAF sensor. NOTICE: Embossed arrows on MAF sensor indicate air flow and must point toward engine. INSTALL OR CONNECT 1. MAF sensor into air duct. 2. Tighten clamps to 4 Nm (36 lb in.). 3. Electrical connector. 4. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Specifications Oil Pressure Switch (For Fuel Pump): Specifications Fuel Pump Switch and Engine Oil Pressure Sensor ................................................................................................................................... 12 Nm (106 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Locations > Fuel Pump/Engine Oil Pressure Indicator Switch > Page 5389 Oil Pressure Switch (For Fuel Pump): Locations Oil Pressure Sensor/Fuel Pump Switch Fuel Pump - Oil Pressure Switch The sensor is threaded into a TEE fitting at the rear of the engine. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions Oil Pressure Switch (For Fuel Pump): Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5392 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5393 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5394 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5395 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5396 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5397 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5398 Oil Pressure Switch (For Fuel Pump): Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5399 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5400 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5401 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5402 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5403 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5404 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5405 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5406 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5407 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5408 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5409 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5410 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5411 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5412 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5413 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5414 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5415 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5416 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5417 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5418 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5419 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5420 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5421 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5422 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5423 Fuel Pump Switch/Engine Oil Pressure Gage Sensor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Diagram Information and Instructions > Page 5424 Fuel Pump Relay Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 5425 Oil Pressure Switch (For Fuel Pump): Description and Operation Fuel Pump - Oil Pressure Switch As a backup system to the fuel pump relay the fuel pump also can be energized by the fuel pump switch and engine oil pressure sensor. The sensor has two internal circuits. One operates the oil pressure indicator or gage on the instrument cluster, and the other is a normally open switch which closes when oil pressure reaches about 28 kPa (4 psi). If the fuel pump relay fails, the fuel pump switch and engine oil pressure sensor runs the fuel pump. An inoperative fuel pump relay can result in long cranking times, particularly if the engine is cold. The fuel pump switch and engine oil pressure sensor energizes the fuel pump as soon as oil pressure reaches about 28 kPa (4 psi). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Oil Pressure Switch (For Fuel Pump) > Component Information > Diagrams > Page 5426 Oil Pressure Switch (For Fuel Pump): Service and Repair Fuel Pump - Oil Pressure Switch REMOVE OR DISCONNECT 1. Disconnect electrical connector. 2. Fuel pump switch and oil pressure sensor. INSTALL OR CONNECT 1. Fuel pump switch and oil pressure sensor. 2. Tighten to 12 Nm (106 lb in.) 3. Electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 5430 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 5431 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5434 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5435 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5436 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5437 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5438 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5439 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5440 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5441 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5442 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5443 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5444 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5445 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5446 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5447 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5448 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5449 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5450 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5451 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5452 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5453 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5454 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5455 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5456 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5457 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5458 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5459 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5460 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5461 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5462 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5463 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5464 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5465 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 5466 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Sensors and Switches - Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 5467 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Specifications Throttle Body: Specifications Throttle Body Attaching Bolts .............................................................................................................. ........................................................ 25 Nm (18 lb ft) Clean Air Cover Attaching Screws .............................................................................................................................................................. 3.2 Nm (28 lb in) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Specifications > Page 5471 Throttle Body Removal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Specifications > Page 5472 Throttle Body: Application and ID Throttle Body Id Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Specifications > Page 5473 Throttle Body Exploded View An eight digit part identification number is stamped on the throttle body casting as shown in the image. Refer to this number if servicing or part replacement is required. For identification of parts during repair, refer to the disassembled view image. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Specifications > Page 5474 Throttle Body: Description and Operation Throttle Body The throttle body assembly is attached to the intake manifold and is used to control air flow into the thereby controlling engine output. The throttle valves within the throttle body are opened by the vehicle operator through the accelerator controls. During engine idle, the throttle valves are almost closed. and air flow control is handled by a fixed air bypass orifice and the Idle Air Control (IAC) valve. To prevent throttle valve icing during cool weather operation, engine coolant is directed through the coolant cavity on the bottom of the throttle body. The throttle body also provides the location for mounting the Throttle Position (TP) sensor and for sensing changes in engine vacuum due to throttle valve position. Vacuum points are located at, above, or below the throttle valve to generate vacuum signals needed by various components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Specifications > Page 5475 Throttle Body: Adjustments To reset Idle Air Control (IAC) valve. 1. Depress accelerator pedal slightly. 2. Start and run engine for 5 seconds. 3. Turn ignition "OFF" for 10 seconds. 4. Restart engine and check for proper idle operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket Throttle Body: Service and Repair Clean Air Cover and Gasket Throttle Body Exploded View REMOVE OR DISCONNECT 1. Resonator. 2. Clean air cover attaching screws. 3. Clean air cover and gasket. ^ Discard the gasket. CLEAN ^ Gasket sealing surfaces. INSTALL OR CONNECT 1. Clean air cover gasket on the throttle body. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket > Page 5478 2. Clean air cover. 3. Attaching screws. Tighten ^ Attaching screws to 3.2 Nm (28 lb in.). 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket > Page 5479 Throttle Body: Service and Repair Idle Air Control/Coolant Cover Assembly Throttle Body Exploded View REMOVE OR DISCONNECT 2. Negative battery cable. 2. Throttle body from intake manifold. ^ Refer to Throttle Body / Service and Repair. DISASSEMBLE 1. Idle Air Control (IAC) valve. 2. IAC valve/coolant cover assembly screws. 3. IAC valve/coolant cover assembly and gasket. ^ Discard gasket Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket > Page 5480 CLEAN AND INSPECT 1. Clean gasket sealing surface. 2. Inspect gasket sealing surface for corrosion or damage that would cause a coolant leak. Replace cover assembly or throttle body if necessary. ASSEMBLE 1. Install new gasket and cover assembly. 2. IAC Valve / coolant cover assembly screws. Tighten ^ IAC Valve / coolant cover assembly screws to 3.2 Nm (28 lb in.). 3. If installing a new IAC valve, measure distance between pintle and mounting surface. If greater than 28mm, use finger pressure to slowly retract the pintle. INSTALL OR CONNECT 1. Install and tighten IAC valve attaching screws Tighten ^ IAC Valve assembly screws to 3 Nm (27 lb in.). 2. Install throttle body to intake manifold. 3. Negative battery cable. 4. Reset IAC valve pintle position. Refer to ADJUSTMENTS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket > Page 5481 Throttle Body: Service and Repair Throttle Body Assembly Removal and Replacement Throttle Body Removal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket > Page 5482 Throttle Body Exploded View REMOVE OR DISCONNECT 1. Negative battery cable. 2. Partially drain cooling system to allow hoses at throttle body to be removed. 3. Resonator. 4. Electrical connectors from Intake Air Temperature (IAT) sensor. 5. Distributor ventilation line at the air intake duct. 6. Air intake duct. 7. Electrical connectors from Throttle Position (TP) sensor and Idle Air Control (IAC) valve. 8. Vacuum lines from throttle body. 9. Coolant hoses from throttle body. 10. Accelerator control cable and cruise control cable. 11. Remove throttle body attaching bolts 12. Remove throttle body assembly and flange gasket, discard gasket CLEAN Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket > Page 5483 ^ Gasket sealing surfaces. NOTICE: Use care in cleaning old gasket material from machined aluminum surfaces as sharp tools may damage sealing surfaces. INSTALL OR CONNECT 1. Throttle body assembly with new flange gasket. 2. Throttle body attaching bolts Tighten ^ Throttle body attaching bolts to 15 Nm (11 lb ft.). 3. Accelerator control cable and cruise control cable. 4. Coolant hoses to throttle body. 5. Vacuum lines to throttle body. 6. Electrical connectors to TP sensor and IAC valve. 5. Distributor ventilation line at the air intake duct. 4. Electrical connectors from IAT sensor. 3. Resonator. 8. Refill cooling system. 9. Connect negative battery cable 10. Ensure accelerator pedal is free. 11. Reset IAC valve position. Refer to ADJUSTMENT PROCEDURES. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Body > Component Information > Service and Repair > Clean Air Cover and Gasket > Page 5484 Throttle Body: Service and Repair Throttle Body Cleaning CLEANING CAUTIONS Do not soak the throttle body in cold immersion type cleaner. The throttle valves have a factory applied sealing compound (DAG material is applied to outside edge of each valve and throttle bore) to prevent air bypass at closed throttle. Strong solvents or brushing will remove the material. To clean the throttle body following dissemble, use a spray type cleaner such as GM X66-A or GM 1052626. Use a shop towel to remove heavy deposits. The Throttle Position (TP) sensor and Idle Air Control (IAC) valve are electrical components and should NOT come in contact with solvent or cleaner, as they may be damaged. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Cable/Linkage > Component Information > Locations Sensor Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Cable/Linkage > Component Information > Locations > Page 5488 Throttle Cable/Linkage: Service and Repair Sensor Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Cable/Linkage > Component Information > Locations > Page 5489 Accelerator Pedal REMOVE OR DISCONNECT 1. Accelerator cable from accelerator pedal 2. Accelerator cable retainer 3. Squeeze accelerator cable cover tangs and push cable through dash panel (Bulkhead). 4. Accelerator cable retaining clip on resonator bracket. 5. Accelerator cable from accelerator cable bracket and throttle body. NOTICE: To prevent possible interference, flexible components (hoses, wires, conduits etc.) must not be routed within 50 mm (2 in.) of moving parts, unless routing is positively controlled. INSTALL OR CONNECT 1. Accelerator cable cover through dash panel (bulkhead). 2. Accelerator cable retainer. 3. Accelerator cable to accelerator pedal. 4. Accelerator cable to accelerator cable bracket and throttle body. 5. Accelerator cable retaining clip on resonator bracket. INSPECT ^ Check for complete throttle opening and closing positions by operating accelerator pedal. Also check for poor carpet fit under the accelerator pedal. Throttle should operate freely without blind between full closed and wide open throttle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications Throttle Position Sensor: Specifications Throttle Position (TP) Sensor Screws .......................................................................................................................................................... 2 Nm (18 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 5493 Throttle Position Sensor: Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Specifications > Page 5494 Component Location - Pictorial View Throttle Body Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Throttle Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5497 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5498 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5499 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5500 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5501 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5502 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5503 Throttle Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5504 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5505 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5506 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5507 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5508 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5509 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5510 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5511 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5512 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5513 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5514 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5515 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5516 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5517 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5518 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5519 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5520 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5521 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5522 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5523 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5524 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5525 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5526 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5527 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5528 Throttle Position Sensor Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 5529 Throttle Position Sensor: Description and Operation Throttle Position (TP) Sensor The Throttle Position (TP) sensor is a potentiometer connected to the throttle shaft on the throttle body and is one of the most important sensors for engine/transmission control. The TP sensor has one end connected to 5 volts from the Powertrain Control Module (PCM) and the other to PCM ground. A third wire is connected to the PCM to measure the voltage from the TP sensor. As the throttle valve angle is changed (accelerator pedal moved), the voltage output of the TP sensor also changes. At a closed throttle position, the voltage output of the TP sensor is low (approximately 0.5 volt). As the throttle valve opens. the output increases so that at wide open throttle, the output voltage should be near 5.0 volts. By monitoring the output voltage from the TP sensor, the PCM can determine fuel delivery based on throttle valve angle (driver demand). A broken or loose TP sensor can cause intermittent bursts of fuel from the injector and cause an unstable idle, because the PCM detects the throttle is moving. If the TP sensor circuit is open, the PCM will set a Diagnostic Trouble Code (DTC) 22. IF the TP sensor circuit is shorted, the PCM will interpret this signal as wide open throttle and a DTC 21 will be set A problem in any of the TP sensor circuits will set either a DTC 21 or 22. Once a DTC is set, the PCM will use a default value for TP sensor, and some vehicle performance will return. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Fuel Delivery and Air Induction > Throttle Position Sensor > Component Information > Diagrams > Page 5530 Throttle Position Sensor: Service and Repair Throttle Position Sensor REMOVE OR DISCONNECT 1. Resonator. 2. Throttle Position Sensor (TPS) sensor electrical connector. 3. Remove two TP sensor attaching screws. 4. TP sensor. NOTICE: The TP sensor is an electrical component and must NOT be soaked in any liquid cleaner or solvent as damage may result. INSTALL OR CONNECT 1. With the throttle valve in the normally closed idle position, install throttle position sensor on throttle body assembly, making sure TP sensor lever lines up with the TP sensor drive lever on the throttle shaft. 2. TP sensor screws. Tighten ^ TP sensor screws to 2.0 Nm (18.0 lb in.). 3. TP Electrical connector. 4. Resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Firing Order > Component Information > Specifications > Ignition Firing Order Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Timing > Number One Cylinder > Component Information > Locations > Number 1 Cylinder Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation Timing Marks and Indicators: Locations Crankshaft Rotation Crankshaft Rotation (Typical Crankshaft Pulley) Crankshaft rotation is clockwise when viewed from in front of the crankshaft pulley as shown in the generic image. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Timing > Timing Marks and Indicators > System Information > Locations > Crankshaft Rotation > Page 5545 Timing Marks and Indicators: Locations Timing Marks The ignition timing is completely controlled by the Powertrain Control Module (PCM). No timing reference marks are provided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5550 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5551 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5552 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5553 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5554 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5555 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5556 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5557 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5558 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5559 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5560 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5561 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5562 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5563 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5564 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5565 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5566 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5567 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5568 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5569 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5570 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5571 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5572 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5573 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5574 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5575 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5576 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5577 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5578 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5579 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5580 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5585 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5586 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5587 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5588 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5589 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5590 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5591 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5592 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5593 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5594 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5595 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5596 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5597 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5598 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5599 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5600 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5601 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5602 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5603 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5604 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5605 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5606 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5607 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5608 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5609 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5610 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5611 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5612 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5613 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5614 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5615 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Distributor, Ignition > Distributor Cap > Component Information > Specifications Distributor Cap: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement Distributor Cap: Service and Repair Replacement Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Distributor cap (30). 2. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 3. Vacuum harness assembly to distributor assembly. 4. Connect four-terminal PCM connector to distributor. 5. Spark plug wire harness assemblies to distributor assembly. 6. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Distributor, Ignition > Distributor Cap > Component Information > Service and Repair > Replacement > Page 5622 Distributor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Distributor, Ignition > Ignition Rotor > Component Information > Specifications Ignition Rotor: Specifications Distributor Bolt / Screw ........................................................................................................................ ..................................................... 12 Nm (106 lb in.) Distributor Cap Bolt / Screw ................................................................................................................ ..................................................... 2.8 N.m (25 lb in.) Distributor Rotor Bolt / Screw .............................................................................................................. ....................................................... 0.7 Nm (6 lb in.) Firing Order ......................................................................................................................................... ............................................ 1 - 8 - 4 - 3 - 6 - 5 - 7 - 2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 5626 Ignition Rotor: Service and Repair Cap - Rotor Assembly Numbers used below refer to image caption. TOOL REQUIRED J 39997 Ignition Distributor Cap Socket J 39998 Ignition Distributor Rotor REMOVE OR DISCONNECT 1. Water pump and crankshaft balancer. 2. Spark plug wire harness assemblies from distributor assembly. 3. Four-terminal Powertrain Control Module (PCM) connector from distributor assembly. 4. Vacuum harness assembly from distributor assembly. 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. 6. Distributor cap (30). 7. Rotor bolts / screws (32) using J 39998 or equivalent. 8. Rotor assembly (32). 9. Distributor cover (33) and shield (34). NOTICE: Do not touch timing disk, sensor or distributor base. INSPECT ^ Distributor base and timing disk, for damage, corrosion or plastic particles. If any are present replace entire distributor assembly. INSTALL OR CONNECT 1. Shield (34) and distributor cover (33). 2. Rotor (32). 3. Rotor bolts / screws (31) using J 39998 or equivalent. Tighten ^ Rotor bolts / screws (31) to 0.7 Nm (61 lb in.). 4. Distributor cap (30). 5. Distributor cap bolts / screws (29) using J 39997 or equivalent. Tighten Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Distributor, Ignition > Ignition Rotor > Component Information > Specifications > Page 5627 ^ Distributor cap bolts / screws (29) to 2.8 Nm (25 lb in.). 6. Vacuum harness assembly to distributor assembly. 7. Connect four-terminal PCM connector to distributor. 8. Spark plug wire harness assemblies to distributor assembly. 9. Crankshaft balancer and water pump assemblies. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications Spark Plug Wire: Specifications Wire Harness Support Bolt / Screw ............................................................................................................................................................ 40 Nm (30 lb ft.) Wire Harness Support Channel Bolt / Screw (Right) ................................................................................................................................ 12 Nm (106 lb in.) Wire Harness Support Channel Bolt/Screw (Left) ..................................................................................................................................... 12 Nm (106 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5631 Spark Plug Wire: Locations Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5632 Spark Plug Harness Routing The spark plug wires run down both sides of the engine block under the exhaust manifolds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5633 Spark Plug Wire: Description and Operation The spark plug wire hamess assemblies use carbon impregnated cord conductors, encased in 8 mm (5 / 16-inch) diameter silicone jackets. The silicone jackets withstand very high temperatures and also provide excellent insulation for the high voltage of the system. Silicone spark plug boots form a tight seal to the spark plugs. The material used to construct spark plug wires is very soft. This wire will withstand more heat and carry a higher voltage, but chaffing and cutting become easier. The spark plug wires must be routed correctly to prevent chafing or cutting. When removing a spark plug wire from a spark plug, twist the boot on the spark plug one-half turn while pulling on the boot. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5634 Spark Plug Wire: Testing and Inspection Inspect spark plug wires visually first for any cuts, burns, or damage. While engine is running, inspect for any arcing to ground or other components. Use a spray bottle to lightly coat the spark plug wires with water while observing idle quality. If idle quality diminishes or engine stalls, spark plug wires should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5635 Spark Plug Wire: Service and Repair Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5636 Spark Plug Harness Routing Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5637 Spark Plug Harness Routing NOTICE: The boots should be twisted one-half turn while removing. Do not pull on the wire harnesses to remove them from the spark plugs. Pull on the boots, or use a tool designed for this purpose. REMOVE OR DISCONNECT Numbers included in this procedure refer to caption numbers in the included images. 1. Left bank spark plug wire boots from spark plugs. 2. Left bank spark plug wire harness support channel bolts / screws (19) and channel. Rear bolt / screw (19) is located behind exhaust manifold takedown. Loosen this bolt / screw using a 10 mm wrench then slide channel upward to disengage from bolt / screw (19). 3. Left bank spark plug wire harness from clip (17) located behind air injection reactor (AIR) pump. 4. Right bank spark plug wire boots from spark plugs. 5. Air intake resonator. With mechanical cooling fan: A. Upper radiator fan shroud, B. Loosen fan pulley nuts. C. Fan belt. D. Mechanical fan and pulley. E. Mechanical fan pulley bracket nuts and bracket. F. Radiator outlet pipe nuts from A/C compressor mounting studs. 6. Serpentine drive belt. 7. Raise and suitably support vehicle. 8. Transmission oil cooler line support bolt / screw from accessory drive bracket. 9. Serpentine drive belt tensioner bolts/screws and tensioner. 10. A/C compressor attaching bolts/screws Reposition A/C compressor to provide access to front wire harness support (27). 11. Right wire harness support bolt / screw (28). 12. Right wire harness from support (27). 13. Left and right bank spark plug wire harnesses (6) from distributor. 14. Left wire harness from clips (17, 20, 21 and 23). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug Wire <--> [Ignition Cable] > Component Information > Specifications > Page 5638 ^ Insert screwdriver into tab on top of clip to disengage. 15. Right wire harness from clips (16, 17, and 21). ^ Insert screwdriver into tab on top of clip to disengage. NOTICE: When replacing spark plug wire harnesses (secondary wiring), route the wire harnesses correctly and through the proper retainers. Failure to route the wire harnesses properly can lead to radio ignition noise and cross-firing of the spark plugs, or shorting of the leads to ground. INSTALL OR CONNECT 1. Right wire harness to clips (16, 17 and 21). 2. Left wire harness to clips (17, 20, 21 and 23). 3. Right wire harness to support (27). 4. Right wire harness support bolt / screw (28). Tighten ^ Bolt / screw (28) to 40 Nm (30 lb ft.). 5. A/C compressor to bracket. 6. A/C compressor attaching bolts / screws and rear bracket nut. Tighten A. A/C compressor bolts / screws to 50 Nm (37 lb ft.). B. A/C compressor rear bracket nut to 41 Nm (30 lb ft.). 7. Serpentine drive belt tensioner and tensioner bolts / screws. Tighten ^ Tensioner bolts / screws to 25 Nm (18 lb ft.). 8. Transmission oil cooler line support bolt / screw. Tighten ^ Oil cooler line support bolt / screw to 1.9 Nm (17 lb in.). 9. Lower vehicle. 10. Serpentine drive belt. With mechanical cooling fan: A. Radiator outlet pipe nuts from A/C compressor mounting studs. Tighten ^ Radiator outlet pipe nuts to 16 Nm (12 lb ft.). B. Mechanical fan pulley bracket nuts and bracket. Tighten ^ Mechanical fan pulley bracket nuts to 50 Nm (37 lb .ft). C. Mechanical fan pulley, fan and nuts. ^ Finger tighten only. D. Fan belt. Tighten ^ Mechanical fan nuts to 26 Nm (19 lb ft.). E. Upper radiator fan shroud. 11. Air intake resonator. 12. Right bank spark plug wire boots to spark plugs. 13. Left bank spark plug wire harness to clip (17) located behind AIR pump. 14. Left bank spark plug wire harness support channel and bolts/screws (19). Rear bolt / screw (19) is located behind exhaust manifold takedown. Slide channel onto bolt / screw (19) then tighten using a 10 mm wrench. 15. Left bank spark plug wire harness boots to spark plugs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Coil > Component Information > Specifications > Electrical Specifications Ignition Coil: Electrical Specifications COIL PACK RESISTANCE SPECIFICATIONS: ^ The OEM service manual does not provide a specification for coil resistance. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Coil > Component Information > Specifications > Electrical Specifications > Page 5643 Ignition Coil: Mechanical Specifications Ignition Coil Assembly Bolt / Screw ........................................................................................................................................................... 25 Nm (18 lb ft.) Ignition Coil Assembly Stud ................................................................................................................. ...................................................... 25 Nm (18 lb ft.) Ignition Coil Module Bolt / Screw ............................................................................................................................................................. 1.7 Nm (15 lb in.) Replacement Gin. Coil to-Bracket Bolt / Screw ......................................................................................................................................... 2.8 Nm (25 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Coil > Component Information > Specifications > Page 5644 Ignition Coil: Locations Engine Left Side Upper Ignition Coil And Module Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Coil > Component Information > Specifications > Page 5645 Ignition Coil: Description and Operation Ignition Coil And Module Assembly Ignition Coil And Module The ignition coil/ignition control module assembly provides spark to the distributor assembly, timed by signals from the ECM. Power (B+) for the ignition coil primary circuit and the ignition control module is supplied by the ignition switch. The ECM combines the camshaft position information supplied by the distributor with other system parameters and calculates the required spark advance and coil dwell. The ECM signals the ignition control module, which turns on the primary current to the ignition coil by grounding the primary circuit, and then turns it off by removing the ground. When the primary current flow stops, high voltage induced in the ignition coil secondary winding becomes the spark voltage for the spark plug. The spark voltage is delivered to the distributor assembly through the coil output (secondary) wire, and then directed to the proper spark plug connector by the distributor rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Coil > Component Information > Specifications > Page 5646 Ignition Coil: Service and Repair Ignition Coil Ignition Coil And Ignition Control Module Numbers used below refer to image caption. REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Four-terminal Powertrain Control Module (PCM) connector at ignition coil module. 3. Ignition coil wiring connectors. 4. Ignition coil harness. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Coil > Component Information > Specifications > Page 5647 5. Studs (5). 6. Ignition coil / Ignition Control Module assembly (8). ^ Do not wipe silicone grease from bottom of ignition coil assembly (8) if it is to he reinstalled. NOTICE: If a new ignition coil assembly is to be installed, a package of silicone grease will be included in the box. This grease is necessary for ignition coil assembly cooling. INSTALL OR CONNECT 1. Spread silicone grease on metal mounting face of ignition coil bracket (14) if necessary, and position ignition coil / Ignition Control module assembly (8) to cylinder head assembly. 2. Studs (5). Tighten ^ Studs (5) to 25 Nm (18 lb ft.). 3. Ignition coil harness. 4. Ignition coil wiring connectors. 5. Four terminal PCM connector to ignition coil module. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Control Module > Component Information > Specifications Ignition Control Module: Specifications Ignition Coil Assembly Bolt / Screw ........................................................................................................................................................... 25 Nm (18 lb ft.) Ignition Coil Assembly Stud ................................................................................................................. ...................................................... 25 Nm (18 lb ft.) Ignition Coil Module Bolt / Screw ............................................................................................................................................................. 1.7 Nm (15 lb in.) Replacement Coil to-Bracket Bolt / Screw ................................................................................................................................................. 2.8 Nm (25 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector Engine Left Side Upper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector > Page 5653 Ignition Control Module: Locations Ignition Module Ignition Coil Ignition Coil And Ignition Control Module The Ignition Control Module is located on the ignition coil bracket assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Control Module > Component Information > Locations > Page 5654 Ignition Control Module: Description and Operation Ignition Coil And Module Assembly Ignition Coil And Module The ignition coil/ignition control module assembly provides spark to the distributor assembly, timed by signals from the ECM. Power (B+) for the ignition coil primary circuit and the ignition control module is supplied by the ignition switch. The ECM combines the camshaft position information supplied by the distributor with other system parameters and calculates the required spark advance and coil dwell. The ECM signals the ignition control module, which turns on the primary current to the ignition coil by grounding the primary circuit, and then turns it off by removing the ground. When the primary current flow stops, high voltage induced in the ignition coil secondary winding becomes the spark voltage for the spark plug. The spark voltage is delivered to the distributor assembly through the coil output (secondary) wire, and then directed to the proper spark plug connector by the distributor rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Control Module > Component Information > Locations > Page 5655 Ignition Control Module: Service and Repair Ignition Coil Ignition Coil And Ignition Control Module Numbers used below refer to image caption. REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Four-terminal Powertrain Control Module (PCM) connector at ignition coil module. 3. Ignition coil wiring connectors. 4. Ignition coil harness. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Ignition Control Module > Component Information > Locations > Page 5656 5. Studs (5). 6. Ignition coil / Ignition Control Module assembly (8). ^ Do not wipe silicone grease from bottom of ignition coil assembly (8) if it is to he reinstalled. DISASSEMBLE 1. Coil (10) from brackets (13 and 14) by drilling out rivets (9). 2. Bolts/screws (12). 3. Ignition control module (11). NOTICE: If a new ignition coil assembly is to be installed, a package of silicone grease will be included in the box. This grease is necessary for ignition coil assembly cooling. ASSEMBLE 1. Spread silicone grease on metal face of ignition control module (11) and on bracket (13) where it seats, and position ignition control module (11) to bracket (13). 2. Bolts / screws (12). Tighten ^ Bolts / screws (12) to 1.7 Nm (15 lb in.). 3. Coil (10) to brackets (13 and 14) using bolts / screws provided with replacement coil (10). Tighten ^ Bolts / screws to 2.8 Nm (25 lb in.). INSTALL OR CONNECT 1. Spread silicone grease on metal mounting face of ignition coil bracket (14) if necessary, and position ignition coil / Ignition Control module assembly (8) to cylinder head assembly. 2. Studs (5). Tighten ^ Studs (5) to 25 Nm (18 lb ft.). 3. Ignition coil harness. 4. Ignition coil wiring connectors. 5. Four terminal PCM connector to ignition coil module. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Locations > Component Locations > Page 5662 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5665 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5666 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5667 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5668 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5669 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5670 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5671 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5672 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5673 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5674 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5675 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5676 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5677 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5678 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5679 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5680 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5681 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5682 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5683 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5684 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5685 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5686 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5687 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5688 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5689 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5690 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5691 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5692 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5693 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5694 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5695 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5696 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Page 5697 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Page 5698 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Knock Sensor > Component Information > Diagrams > Page 5699 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Specifications Ignition Control Module: Specifications Ignition Coil Assembly Bolt / Screw ........................................................................................................................................................... 25 Nm (18 lb ft.) Ignition Coil Assembly Stud ................................................................................................................. ...................................................... 25 Nm (18 lb ft.) Ignition Coil Module Bolt / Screw ............................................................................................................................................................. 1.7 Nm (15 lb in.) Replacement Coil to-Bracket Bolt / Screw ................................................................................................................................................. 2.8 Nm (25 lb in.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector Engine Left Side Upper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Ignition Coil Module Connector > Page 5706 Ignition Control Module: Locations Ignition Module Ignition Coil Ignition Coil And Ignition Control Module The Ignition Control Module is located on the ignition coil bracket assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 5707 Ignition Control Module: Description and Operation Ignition Coil And Module Assembly Ignition Coil And Module The ignition coil/ignition control module assembly provides spark to the distributor assembly, timed by signals from the ECM. Power (B+) for the ignition coil primary circuit and the ignition control module is supplied by the ignition switch. The ECM combines the camshaft position information supplied by the distributor with other system parameters and calculates the required spark advance and coil dwell. The ECM signals the ignition control module, which turns on the primary current to the ignition coil by grounding the primary circuit, and then turns it off by removing the ground. When the primary current flow stops, high voltage induced in the ignition coil secondary winding becomes the spark voltage for the spark plug. The spark voltage is delivered to the distributor assembly through the coil output (secondary) wire, and then directed to the proper spark plug connector by the distributor rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 5708 Ignition Control Module: Service and Repair Ignition Coil Ignition Coil And Ignition Control Module Numbers used below refer to image caption. REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Four-terminal Powertrain Control Module (PCM) connector at ignition coil module. 3. Ignition coil wiring connectors. 4. Ignition coil harness. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Relays and Modules - Ignition System > Ignition Control Module > Component Information > Locations > Page 5709 5. Studs (5). 6. Ignition coil / Ignition Control Module assembly (8). ^ Do not wipe silicone grease from bottom of ignition coil assembly (8) if it is to he reinstalled. DISASSEMBLE 1. Coil (10) from brackets (13 and 14) by drilling out rivets (9). 2. Bolts/screws (12). 3. Ignition control module (11). NOTICE: If a new ignition coil assembly is to be installed, a package of silicone grease will be included in the box. This grease is necessary for ignition coil assembly cooling. ASSEMBLE 1. Spread silicone grease on metal face of ignition control module (11) and on bracket (13) where it seats, and position ignition control module (11) to bracket (13). 2. Bolts / screws (12). Tighten ^ Bolts / screws (12) to 1.7 Nm (15 lb in.). 3. Coil (10) to brackets (13 and 14) using bolts / screws provided with replacement coil (10). Tighten ^ Bolts / screws to 2.8 Nm (25 lb in.). INSTALL OR CONNECT 1. Spread silicone grease on metal mounting face of ignition coil bracket (14) if necessary, and position ignition coil / Ignition Control module assembly (8) to cylinder head assembly. 2. Studs (5). Tighten ^ Studs (5) to 25 Nm (18 lb ft.). 3. Ignition coil harness. 4. Ignition coil wiring connectors. 5. Four terminal PCM connector to ignition coil module. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Camshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5715 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5716 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5717 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5718 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5719 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5720 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5721 Camshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5722 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5723 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5724 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5725 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5726 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5727 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5728 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5729 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5730 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5731 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5732 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5733 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5734 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5735 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5736 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5737 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5738 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5739 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5740 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5741 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5742 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5743 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5744 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Camshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5745 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions Crankshaft Position Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5750 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5751 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5752 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5753 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5754 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5755 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5756 Crankshaft Position Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5757 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5758 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5759 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5760 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5761 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5762 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5763 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5764 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5765 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5766 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5767 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5768 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5769 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5770 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5771 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5772 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5773 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5774 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5775 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5776 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5777 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5778 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5779 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Crankshaft Position Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5780 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Specifications Knock Sensor: Specifications Knock (KS) Sensor .............................................................................................................................. ........................................................ 19 Nm (14 lb ft.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Locations > Component Locations Knock Sensor: Component Locations Engine, Left Side Lower Lower Right Side Of Engine There are two knock sensors (KS), located in the engine block, one on each side. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Locations > Component Locations > Page 5786 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions Knock Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5789 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5790 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5791 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5792 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5793 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5794 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5795 Knock Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5796 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5797 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5798 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5799 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5800 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5801 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5802 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5803 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5804 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5805 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5806 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5807 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5808 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5809 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5810 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5811 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5812 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5813 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5814 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5815 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5816 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5817 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5818 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5819 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Diagram Information and Instructions > Page 5820 Knock Sensor Circuit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 5821 Knock Sensor: Description and Operation Knock Sensor (KS) Sensor Knock Sensor Cut-away Varying octane levels in today's gasoline can cause detonation in high performance engines. Detonation is sometimes called spark knock. To control spark knock, a Knock Sensor (KS) system is used. This system is designed to retard spark timing up to 20° to reduce spark knock in the engine. This allows the engine to use maximum spark advance to improve driveability and fuel economy. The knock sensor system is used to detect engine detonation. The Powertrain Control Module (PCM) will retard the spark timing based on signals from the KS module. The knock sensors produce an AC voltage which is sent to the KS module. The amount of AC voltage produced by the sensors is determined by the amount of knock. This signal voltage is input to the PCM. The PCM then adjusts the Ignition Control (IC) to reduce spark knocking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 5822 Knock Sensor: Testing and Inspection The Tech 1 (or equivalent) has several positions for diagnosing the Knock Sensor (KS) circuit. "Knock signal" is used to monitor the input signal from the knock sensor. This position should display "YES" to indicate when a knock is being detected. "Knock retard" is the indication of how much the Powertrain Control Module (PCM) is retarding the spark. Diagnostic Trouble Code (DTC) 43 is designed to diagnose the knock sensor circuit. Problems encountered with this circuit should set DTC 43. However, if no DTC 43 was set but the KS system is suspected, refer to CHART C-5. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Sensors and Switches - Ignition System > Knock Sensor > Component Information > Diagrams > Page 5823 Knock Sensor: Service and Repair REMOVE OR DISCONNECT 1. Negative battery cable. 2. Drain cooling system. 3. Raise vehicle. 4. Wiring harness connector from knock sensor. WARNING: Engine coolant may be hot. The knock sensor is mounted in the engine block cooling passage. Engine coolant will drain when the knock sensor is removed. 5. Knock sensor from block. NOTICE: Do NOT apply thread sealant to sensor threads. Sensor is coated at factory and applying additional sealant will affect the sensor's ability to detect detonation. INSTALL OR CONNECT 1. Knock sensor into block. Tighten ^ Sensor to 19 Nm (14 lb ft.). 2. Wiring harness connector to knock sensor. 3. Lower vehicle. 4. Refill cooling system and pressure test for leaks. 5. Negative battery cable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug > Component Information > Specifications Spark Plug: Specifications Spark Plug Install Torque .................................................................................................................... ........................................................ 27 Nm (20 lb ft.) Spark Plug Gap ................................................................................................................................... ........................................................ 1.27 mm (0.050") Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug > Component Information > Specifications > Page 5827 Spark Plug Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug > Component Information > Specifications > Page 5828 Spark Plug: Service Precautions It is important that technicians wash their hands after handling coated spark plugs and before smoking. The coating itself is a nonhazardous material and incidental contact will not cause any adverse affects. However, exposure to polymer vapors (the result of a cigarette being coated from handling, then burned) may cause flu like symptoms and should be avoided. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug > Component Information > Specifications > Page 5829 Spark Plug ID Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug > Component Information > Specifications > Page 5830 Spark Plug: Description and Operation Platinum-tipped, resistor-type, tapered-seat spark plugs are used on the engine assembly. No gasket is used on these tapered-seat spark plugs. When replacing spark plugs, use only the type specified. Normal service is assumed to be a mixture of idling, slow speed, and high speed driving. Occasional or intermittent high-speed driving is needed for good spark plug performance. It gives increased combustion heat, burning away carbon or oxides that have built up from frequent idling, or continual stop-and-go driving. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug > Component Information > Specifications > Page 5831 Spark Plug: Testing and Inspection WORN OR DIRTY Worn or dirty spark plugs may give satisfactory operation at idling speed, but frequently fail at higher rpm. Faulty spark plugs may cause poor fuel economy, power loss, loss of speed, hard starting and generally poor engine performance. Follow the scheduled maintenance service recommendations to assure satisfactory spark plug performance. NORMAL Normal spark plug operation will result in brown to grayish - tan deposits appearing on the portion of the spark plug that projects into the cylinder area. A small amount of red - brown, yellow, and white powdery material may also be present on the insulator tip around the center electrode. These deposits are normal combustion by-products of fuels and lubricating oils with additives. MISFIRING Engine assemblies which are not running properly are often referred to as "misfiring." This means the ignition spark is not igniting the fuel/air mixture at the proper time, While other ignition and fuel system causes must also be considered, possible causes include ignition system conditions which allow the spark voltage to reach ground in some other manner than by jumping across the air gap at the tip of the spark plug, leaving the fuel/air mixture unburned. Misfiring may also occur when the tip of the spark plug becomes overheated and ignites the mixture before the spark jumps. This is referred to as "pre-ignition." CARBON FOULING Carbon fouling of the spark plug is indicated by dry, black carbon (soot) deposits on the portion of the spark plug in the cylinder. Excessive idling and slow speeds under light engine loads can keep the spark plug temperatures so low that these deposits are not burned off. Over - rich fuel mixtures or poor ignition system output may also be the cause. OIL FOULING Oil fouling of the spark plug is indicated by wet oily deposits on the portion of the spark plug in the cylinder. This may be caused by oil getting past worn piston rings. This condition also may occur during break-in of new or newly overhauled engine assemblies. DEPOSITS Deposit fouling of the spark plug occurs when the normal red - brown, yellow or white deposits of combustion by - products become sufficient to cause misfiring. In some cases, these deposits may melt and form a shiny glaze on the insulator around the center electrode. If the fouling is found in only one or two cylinders, valve stem clearances or intake valve seals may be allowing excess lubricating oil to enter the cylinder, particularly if the deposits are heavier on the side of the spark plug that was facing the intake valve. CRACKED OR BROKEN Cracked or broken insulators may be the result of improper installation or heat shock to the insulator material. Upper insulators can be broken when a poorly fitting tool is used during installation or removal, or when the park plug is hit from the outside. Cracks in the upper insulator may be inside the shell and not visible. Also, the breakage may not cause problems until oil or moisture penetrates the crack later. A broken or cracked lower insulator tip (around the center electrode) may result from "heat shock" (spark plug suddenly operating too hot). "Heat shock" breakage in the lower insulator tip generally occurs during severe engine operating conditions (high speeds or heavy loading) and may be caused by over - advanced timing or low grade fuels. Heat shock refers to a rapid increase in the tip temperature that causes the insulator material to crack. Damage during gapping can happen if the gapping tool is pushed against the center electrode or the insulator around it, causing the insulator to crack. When gapping a spark plug, make the adjustment by only bending the ground side terminal, keeping the tool clear of other parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Ignition System > Spark Plug > Component Information > Specifications > Page 5832 Spark Plug: Service and Repair Spark Plug Assembly REMOVE OR DISCONNECT 1. Be sure ignition switch is in "OFF" or "LOCK" position. 2. Spark plug wire harness assemblies from spark plugs. Refer to "Spark Plug Wire Harness Assembly Replacement" in this section. ^ Note positions of wires before removing. NOTICE: Clean dirt and debris from spark plug recess areas. 3. Spark plugs from cylinder head assemblies. NOTICE: Be sure spark plugs thread smoothly into cylinder head assemblies and are fully seated. Cross threading or failing to fully seat spark plugs can cause overheating of spark plugs, exhaust blow-by, or thread damage. Follow recommended torque specifications carefully. Over or under - tightening can also cause severe damage to cylinder head assemblies or spark plug. Check spark plug gap using a wire type gauge before installing. If spark plug gaps are not adjusted correctly, engine idle quality may be seriously affected. A wire type gauge must be used (as opposed to a flat feeler type gauge) to insure an accurate reading. INSTALL OR CONNECT 1. Spark plugs to cylinder head assemblies. Tighten ^ Spark plugs to 27 Nm (20 lb ft.). 2. Spark plug wire harness assemblies, routed properly as note during removal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Torque Converter Clutch Solenoid: Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 5840 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 5841 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > Page 5842 Torque Converter Clutch Solenoid: Service and Repair REPLACE 1. Raise and support vehicle. 2. Disconnect heated oxygen sensor. 3. Remove catalytic converter to muffler attaching bolts and nuts. 4. Remove catalytic converter hanger to catalytic converter bolts. 5. Remove righthand side dampener assembly. 6. Remove nuts holding exhaust pipe to exhaust manifold. 7. Remove converter and pipe assembly from vehicle. 8. Remove oil pan and oil filter assembly. 9. Disconnect external wiring harness from transmission pass through connector. 10. Remove accumulator cover attaching bolts. 11. Remove 1-2 accumulator cover, piston and spring. 12. Disconnect electrical connectors. 13. Remove pressure control solenoid retainer bolt, then the retainer and solenoid. 14. Remove TCC solenoid retaining bolts. 15. Remove pass-through electrical connector from transmission case by positioning the small end of power piston seal protector and diaphragm retainer installer tool No. J-28458 or equivalent, over the top of the connector, then twist tool to release the four tabs while at the same time pulling the harness through the case. 16. Remove TCC solenoid with wiring harness from transmission case. 17. Reverse procedure to install, noting the following: a. Tighten TCC solenoid retaining bolt to specification. b. Tighten pressure control solenoid retaining bolt to specification. c. When installing 1-2 accumulator piston to accumulator cover, the piston legs must face towards the case. d. Tighten accumulator attaching bolts to specification Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 5853 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 5854 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 5855 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 5861 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 5862 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 5863 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 5864 Shift Indicator: Description and Operation DESCRIPTION This lamp is used on most models equipped with manual transmission. OPERATION The Upshift lamp is illuminated to inform the driver of ideal shift points, with improved fuel economy as the specific objective. When the light is illuminated, the transmission should be shifted to the next highest gear, if driving conditions permit such an action. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 5865 Shift Indicator: Service and Repair If upshift indicator is not working properly, perform the following test. 1. Disconnect ECM connector C1. 2. Place ignition switch in run. 3. Measure voltage at terminal A2 of ECM connector. 4. If battery voltage is present, further ECM diagnosis is necessary. 5. If battery voltage is not present, repair open circuit in brown/black wire, circuit 456. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 5872 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 5873 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5876 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5877 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5878 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5879 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5880 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5881 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5882 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5883 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5884 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5885 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5886 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5887 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5888 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5889 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5890 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5891 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5892 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5893 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5894 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5895 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5896 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5897 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5898 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5899 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5900 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5901 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5902 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5903 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5904 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5905 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5906 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5907 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 5908 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Temperature Sensor/Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5913 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5914 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5915 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5916 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5917 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5918 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5919 Transmission Temperature Sensor/Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5920 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5921 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5922 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5923 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5924 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5925 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5926 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5927 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5928 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5929 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5930 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5931 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5932 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5933 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5934 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5935 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5936 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5937 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5938 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5939 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5940 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5941 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5942 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5943 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 5944 Transmission Range Switch Assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Page 5945 Transmission Temperature Sensor/Switch: Description and Operation The Transmission Fluid Temperature (TFT) sensor is a thermistor (a device that changes resistance according to changes in temperature) used to indicate transmission fluid temperature. High sensor resistance produces high signal input voltage which corresponds to low fluid temperature. Low sensor resistance produces low signal input voltage which corresponds to high fluid temperature. The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following: ^ Torque Converter Clutch (TCC) apply and release schedules. ^ Hot mode determination. ^ Shift quality. The TFT sensor is part of the transmission range fluid pressure switch assembly and is attached to the control valve body within the transmission. A fault in the Transmission Fluid Temperature (TFT) sensor circuit will set a DTC 58. 59 or 79. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > Customer Interest: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set PROM - Programmable Read Only Memory: Customer Interest AIR Pump - Hesitation on Acceleration/DTC's Set File In Section: 06 Engine/Propulsion System Bulletin No.: 01-06-04-011 Date: March, 2001 TECHNICAL Subject: Water in AIR Pump and/or DTC P0410, P0412, P0415, P0416, P0100, P0101, P0102 or DTC 48 (AIR System Disable Procedure) Models: 1995-1996 Buick Roadmaster 1995-1996 Cadillac Fleetwood 1995-1996 Chevrolet Caprice, Impala SS with 4.3L or 5.7L Engine (VINs W, P - RP0s L99, LT1) Condition ^ Some customers may comment of a hesitation during heavy/full throttle acceleration. ^ A 1996 vehicle may also set any of the following DTCs: - P0410 - P0412 - P1415 - P1416 - P0100 - P0101 - P0102 ^ A 1995 vehicle may set a DTC 48. ^ There will also be evidence of water in the AIR pump. Cause Under high engine speed and load conditions, hot exhaust gasses may leak past the air check valves. As the exhaust gasses in the air tube cool, water vapors collect into the AIR pump. As the vehicle is driven, condensation from the AIR pump may come into contact with the Mass Airflow Sensor through the AIR inlet hose. This condition may cause a hesitation on acceleration and may also set the DTCs. Correction To correct this condition, a Secondary AIR Injection Pump disable procedure has been developed. (It has been determined that the Secondary AIR Injection system is not required to meet emission requirements for these vehicles only.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > Customer Interest: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set > Page 5954 1. Locate the relay center (1) and air cleaner box (2). 2. Remove the AIR hose and clamp (1) from the air cleaner box. 3. Insert the plug (2) into the air cleaner box AIR hose inlet (3). 4. Install the AIR hose and clamp (1) to the air cleaner box. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > Customer Interest: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set > Page 5955 5. Remove the cover (1) from the relay center (3). 6. Remove AIR pump relay (2) from the relay center (3). 7. Install the relay cover (1) 8. Install new emission label to radiator support (3). 9. Update vehicle calibration. (1995 4.3 L L99 Caprice, and 1996 vehicles). Parts Information Parts are currently available from GMSPO. Calibration Information The Calibrations are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline starting February 2001, Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > Customer Interest: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set > Page 5956 on the TIS 2000 version TIS 2.0/2001 data update or later. Warranty Information For vehicles repaired under warranty, use table shown. 1995 4.3 L (RP0 L99) Caprice and 1996 vehicles should also use additional table shown add time for reprogramming. DISCLAIMER Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > Customer Interest: > 576517A > Jun > 96 > PCM - Chuggle/Surge/Intermittent DTC 32 PROM - Programmable Read Only Memory: Customer Interest PCM - Chuggle/Surge/Intermittent DTC 32 File In Section: 6E - Engine Fuel & Emission Bulletin No.: 57-65-17A Date: June, 1996 Subject: Chuggle or Surge and an Intermittent DTC 32 (Reflash Calibration) Models: 1994-96 Buick Roadmaster 1994-96 Cadillac Fleetwood 1994-96 Chevrolet Caprice, Impala SS with 5.7L Engine (VIN P - RPO LT1) and 4L60-E Automatic Transmission This bulletin is being revised to add the 1996 model year and to update the parts information chart. Please discard Corporate Bulletin Number 57-65-17 (Section 6E - Engine Fuel and Emission). Condition Some owners may comment on a chuggle or a surge condition between 40-65 mph (64-104 kmph). Also some vehicles may set an intermittent DTC 32 (1994-95 vehicles only). Correction Install the proper flash calibration listed from table in Parts Information. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > Customer Interest: > 576517A > Jun > 96 > PCM - Chuggle/Surge/Intermittent DTC 32 > Page 5961 Parts Information Warranty Information For vehicles repaired under warranty, use: Labor Operation Labor Time J6355 Use published labor operation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set PROM - Programmable Read Only Memory: All Technical Service Bulletins AIR Pump - Hesitation on Acceleration/DTC's Set File In Section: 06 Engine/Propulsion System Bulletin No.: 01-06-04-011 Date: March, 2001 TECHNICAL Subject: Water in AIR Pump and/or DTC P0410, P0412, P0415, P0416, P0100, P0101, P0102 or DTC 48 (AIR System Disable Procedure) Models: 1995-1996 Buick Roadmaster 1995-1996 Cadillac Fleetwood 1995-1996 Chevrolet Caprice, Impala SS with 4.3L or 5.7L Engine (VINs W, P - RP0s L99, LT1) Condition ^ Some customers may comment of a hesitation during heavy/full throttle acceleration. ^ A 1996 vehicle may also set any of the following DTCs: - P0410 - P0412 - P1415 - P1416 - P0100 - P0101 - P0102 ^ A 1995 vehicle may set a DTC 48. ^ There will also be evidence of water in the AIR pump. Cause Under high engine speed and load conditions, hot exhaust gasses may leak past the air check valves. As the exhaust gasses in the air tube cool, water vapors collect into the AIR pump. As the vehicle is driven, condensation from the AIR pump may come into contact with the Mass Airflow Sensor through the AIR inlet hose. This condition may cause a hesitation on acceleration and may also set the DTCs. Correction To correct this condition, a Secondary AIR Injection Pump disable procedure has been developed. (It has been determined that the Secondary AIR Injection system is not required to meet emission requirements for these vehicles only.) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set > Page 5967 1. Locate the relay center (1) and air cleaner box (2). 2. Remove the AIR hose and clamp (1) from the air cleaner box. 3. Insert the plug (2) into the air cleaner box AIR hose inlet (3). 4. Install the AIR hose and clamp (1) to the air cleaner box. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set > Page 5968 5. Remove the cover (1) from the relay center (3). 6. Remove AIR pump relay (2) from the relay center (3). 7. Install the relay cover (1) 8. Install new emission label to radiator support (3). 9. Update vehicle calibration. (1995 4.3 L L99 Caprice, and 1996 vehicles). Parts Information Parts are currently available from GMSPO. Calibration Information The Calibrations are electronic calibrations and are NOT available from GMSPO. Calibrations will be available from Techline starting February 2001, Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 01-06-04-011 > Mar > 01 > AIR Pump - Hesitation on Acceleration/DTC's Set > Page 5969 on the TIS 2000 version TIS 2.0/2001 data update or later. Warranty Information For vehicles repaired under warranty, use table shown. 1995 4.3 L (RP0 L99) Caprice and 1996 vehicles should also use additional table shown add time for reprogramming. DISCLAIMER Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 99-06-04-053 > Nov > 99 > PROM - Powertrain Control Module Reprogramming PROM - Programmable Read Only Memory: All Technical Service Bulletins PROM - Powertrain Control Module Reprogramming File In Section: 06 - Engine/Propulsion System Bulletin No.: 99-06-04-053 Date: November, 1999 INFORMATION Subject: Powertrain Control Module (PCM) Reprogramming (Do Not Reprogram Using the Same Download Files as Those Already Present in The Control Module) Models: 1990-2000 Passenger Cars and Trucks with Reprogrammable PCM It is strongly recommended to NOT reinstall the same software and/or calibration download file(s) into the powertrain control module as those that are already present in the PCM. There is no technical reason that the download files inside the PCM would ever become corrupted after the control module had previously been successfully programmed. A P0601 (Control Module Read Only Memory) Diagnostic Trouble Code would set in memory and the MIL would be illuminated if the controller memory became corrupted. The Techline Information System 2000 (TIS 2000) PC, combined with vehicle information gained through the Tech 2, can determine when an attempt to reprogram a PCM using the same download files (as those already in the control module) is being requested. If this is attempted, the TIS 2000 PC currently displays the following message: Notice: THE CALIBRATION SELECTED IS THE CURRENT CALIBRATION IN THE CONTROL MODULE. PROGRAMMING WITH THE SAME DOWNLOAD FILES IS NOT AN EFFECTIVE REPAIR. SELECT ( YES ) TO CONTINUE PROGRAMMING THE CONTROL MODULE,OR ( NO ) TO CANCEL. Effective in the first quarter of 2000, the TIS 2000 PC will indicate: Important: THE CALIBRATION SELECTED IS ALREADY THE CURRENT CALIBRATION IN THE CONTROL MODULE. REPROGRAMMING WITH THE SAME DOWNLOAD FILE IS NOT ALLOWED. Certain learned values, such as: (but not limited to) ^ fuel trim (previously known as block learn memory), ^ IAC learned position in various park/neutral and air conditioning on/off combinations, ^ certain OBDII diagnostic thresholds, ^ automatic transmission shift adapts will revert back to their unlearned starting point values after a reprogramming event occurs. It is feasible that the engine or transmission might temporarily operate differently after a reprogramming event, until these values are re-learned. Relearning occurs while operating the vehicle through normal driving routines. If the same download files are simply reinstalled, any changes noticed in engine operation will likely disappear in a short amount of time and/or driving distance. Reprogramming the control module with the same download files that already exist in the module will only accomplish a warranty claim for a non-effective repair, and a likely comeback. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter PROM - Programmable Read Only Memory: All Technical Service Bulletins PROM - Reprogram Using Off Board Program Adapter File In Section: 6E - Engine Fuel & Emission Bulletin No.: 73-65-13 Date: March, 1997 INFORMATION Subject: Reprogramming Capability using the Off Board Programming Adapter Models: 1993-97 Passenger Cars and Trucks (Applicable Reprogrammable Vehicles) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 5978 The General Motors vehicles contain Electronically Reprogrammable Devices (i.e. PCM, VCM, ECM). These vehicles cannot be programmed through PROM replacement, however service programming capability is available through the Tech 1/1A, Tech 2 and Techline terminals via direct or remote programming. The Environmental Protection Agency (EPA) has requested that all new vehicle manufacturers ensure their dealers/retailers are aware that they are responsible for providing customers access to reprogramming services at a reasonable cost and in a timely manner. Although programming of controllers has become a common service practice at GM dealers/retailers, the EPA has received reports from consumers and the aftermarket repair industry that they were unable to purchase a new (programmed) Electronically Reprogrammable Device (ERD) over-the-counter. As a result, on August 1, 1995, the Federal Government issued a regulation requiring all manufacturers to make available reprogramming to the independent aftermarket by December 1, 1997. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 5979 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 5980 Today, the Off Board Programming Adapter (OBPA) is used to reprogram ERD's sold over-the-counter. For all practical purposes, the OBPA takes the place of the vehicle when the vehicle is not available. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 5981 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 5982 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 5983 The list of dealerships/retailers currently own the OBPA (see Attachments 1 - 3). These locations are equipped to provide over-the-counter preprogrammed ERD's. The hardware required to perform reprogramming in addition to the OBPA is a Techline terminal, Tech 1/1A and associated cables and adapters. THE TECH 2 SHOULD NOT BE USED WITH THE OBPA AT THIS TIME BECAUSE OF INADEQUATE OBPA GROUNDING. The current OBPA can support reprogramming on all late model General Motor's vehicles except: ^ Premium V-8's ^ 1996 Diesel Truck ^ Cadillac Catera Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 5984 ^ All 1997 programmable vehicles (requires use of the Tech 2) A modification to the OBPA is being offered by Kent-Moore to support these additional vehicles and to allow reprogramming using the Tech 2. The revisions to the OBPA for the Tech 2 is very important as the Tech 2 is the only tool used for service programming for 1997 and future vehicles. To have the modifications performed, contact Kent-Moore at (800) 345-2233. The revisions (part number J 41207 REV-C) are free of charge for GM dealerships/retailers. A dealership/retailer can purchase the OBPA by contacting Kent-Moore (part number J 41207-C). Support on how to use the OBPA is provided by the Techline Customer Support Center (TCSC) at (800) 828-6860 (English) or (800) 503-3222 (French). If you need to purchase an OBPA and/or cable, contact Kent-Moore at (800) 345-2233. The OBPA retails for $695.00 (includes all revisions 1-4) under part number J 41207-C. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 576517A > Jun > 96 > PCM - Chuggle/Surge/Intermittent DTC 32 PROM - Programmable Read Only Memory: All Technical Service Bulletins PCM Chuggle/Surge/Intermittent DTC 32 File In Section: 6E - Engine Fuel & Emission Bulletin No.: 57-65-17A Date: June, 1996 Subject: Chuggle or Surge and an Intermittent DTC 32 (Reflash Calibration) Models: 1994-96 Buick Roadmaster 1994-96 Cadillac Fleetwood 1994-96 Chevrolet Caprice, Impala SS with 5.7L Engine (VIN P - RPO LT1) and 4L60-E Automatic Transmission This bulletin is being revised to add the 1996 model year and to update the parts information chart. Please discard Corporate Bulletin Number 57-65-17 (Section 6E - Engine Fuel and Emission). Condition Some owners may comment on a chuggle or a surge condition between 40-65 mph (64-104 kmph). Also some vehicles may set an intermittent DTC 32 (1994-95 vehicles only). Correction Install the proper flash calibration listed from table in Parts Information. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 576517A > Jun > 96 > PCM - Chuggle/Surge/Intermittent DTC 32 > Page 5989 Parts Information Warranty Information For vehicles repaired under warranty, use: Labor Operation Labor Time J6355 Use published labor operation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming PROM - Programmable Read Only Memory: All Technical Service Bulletins SPS/FLASH EPROM Programming File In Section: 6E - Engine Fuel & Emission Bulletin No.: 53-65-08 Date: January, 1996 INFORMATION Subject: SPS/FLASH EPROM Programming Models: 1993-96 Passenger Cars and Trucks Applicable Reprogrammable Vehicles This bulletin is being issued to assist technicians in reprogramming vehicles and should be used in conjunction with instructions provided on your Techline Terminal and in your Techline Terminal User's Manual. THE TECHLINE TERMINAL (T-20, T-50, T-60) HAS BEEN ABLE TO DO 1996 VEHICLE PROGRAMMING THROUGH THE DIRECT METHOD SINCE 1996 VEHICLES HAVE BEEN AVAILABLE IN THE DEALERSHIPS/RETAIL FACILITIES. THE TECHLINE CD-ROM TITLED DISC 13 CONTAINS THE SOFTWARE NEEDED TO PROGRAM ALL 1996 VEHICLES WITH A TECH 1 (REMOTE PROGRAMMING METHOD). SPS Tips 1. BATTERY VOLTAGE SHOULD BE CHECKED. A FULLY CHARGED BATTERY IS NECESSARY BEFORE REPROGRAMMING TAKES PLACE. THE VEHICLE BATTERY SHOULD NOT BE CONNECTED TO A BATTERY CHARGER DURING A PROGRAMMING EVENT INCORRECT VOLTAGE COULD CAUSE PROGRAMMING AND/OR CONTROL MODULE FAILURE. During programming, the control module depends on the battery as its sole source of power. Also during programming, the vehicle's components (i.e. blower motor) are set to a default mode which may be turned on, placing additional draw on the vehicle's battery. If the voltage goes outside the specified range (11 to 14 volts) the controllers and the Techline equipment will stop communicating. If this happens, it could cause the control module to become inoperable and require replacement. 2. CHECK THE INTEGRITY OF THE TECH 1 CABLES, MAKE SURE THEY ARE NOT FRAYED, BROKEN OR TWISTED. Loss of communication for any reason will require additional time in completing the reprogramming event. 3. IF USING A TECH 1, YOUR MASS STORAGE CARTRIDGE (MSC) MUST BE UPDATED TO REFLECT THE MOST CURRENT UPDATE OFFERED ON THE TECHLINE CD-ROM. DISC 13, 1995 WAS THE FIRST CD-ROM THAT HAD REMOTE PROGRAMMING SUPPORT If your MSC is not updated to reflect the current software version on the Techline Terminal, in some situations the software will not be capable of interpreting the information that is requested from the vehicle. 4. T-100 TERMINALS (CAMS) ARE NOT CAPABLE OF PROGRAMMING OBD II VEHICLES THROUGH THE DIRECT METHOD. A TECH 1 MUST BE USED (REMOTE METHOD) WHEN REPROGRAMMING WITH A T-100. The T-100 terminals communicate with vehicles through a DLC (ALDL) card and cable found within the T-100's computer. The DLC (ALDL) card is not capable of communicating at the new baud rate used with OBD II. 5. PROGRAMMING IS NOT NEEDED IF THE CURRENT CALIBRATION IS THE SAME AS THE SELECTED CALIBRATION. 6. IF PROGRAMMING A NEW CONTROL MODULE, YOU MUST REQUEST INFORMATION FROM THE NEW CONTROL MODULE. The security information that is needed for a control module to be programmed is stored in the new control module. The security information must be requested from the control module to be programmed. At that point, the control module can be successfully programmed. This requesting of security information takes place in both the direct and remote methods. The request is automatic when using the direct method. Looking at the calibration stored in the old controller may be helpful in selecting the calibration from the CD-ROM for the new controller. 7. WHEN PROGRAMMING OBD II VEHICLES WITH A TECH 1 (REMOTE PROGRAMMING METHOD), A VEHICLE INTERFACE MODULE (VIM) IS REQUIRED. The VIM allows the Tech 1 to communicate with the OBD II vehicles. The VIM is necessary for all other Tech 1 diagnostics on OBD II vehicles. VIMs are no longer on backorder. If you are interested in obtaining additional VIMs, call 1-800-GM-TOOLS and ask for VIM kit part number 7000041. 8. DISCONNECT THE TECH I AND VIM FROM THE VEHICLE BETWEEN RETRIEVING DATA AND PROGRAMMING THE VEHICLE. If the VIM remains powered up after data is requested, a communication problem may result when the reprogramming function is performed. 9. WHEN CONNECTING THE TECH 1 TO A TECHLINE TERMINAL (EXCEPT T-100 CAMS), ALWAYS CONNECT THE FLAT GRAY R5232 CABLE FIRST AND THEN THE POWER ADAPTER. FAILURE TO DO SO COULD RESULT IN A LOSS OF INFORMATION Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming > Page 5994 STORED ON THE TECH 1. When power is turned on to the Tech 1, it looks for the RS232 connection. If it does not see the connection, the Tech 1 in some cases, will erase the information stored for download. 10. DO NOT DISCONTINUE OR INTERRUPT THE PROGRAM LOADING PROCESS TO THE VEHICLE. This will result in a programming error and could prevent the Electronic Control Module (ECM) from functioning properly. 11. AFTER PROGRAMMING IS COMPLETE, PRESS "EXIT". MAKE SURE THE KEY IS CYCLED OFF FOR APPROXIMATELY 10 SECONDS THEN BACK ON. Some vehicles will lose component settings (PMC/IAC Valve). Cycling the key off two times (Off for 30 seconds, On for 10 then repeat a second time) will allow for resetting of the components. Start the vehicle to ensure programming was successful. FOR CADILLAC VEHICLES ONLY a. DUE TO OTHER MODULES ON THE DATA LINE TRYING TO COMMUNICATE WITH THE ECM DURING PROGRAMMING, SOME COMMUNICATION CODES MAY BE SET After programming is complete, clear any codes and verify they do not reset. b. TO HELP MINIMIZE BATTERY DRAW DURING ECM PROGRAMMING, DISCONNECT THE BLOWER MOTOR (AT THE CONNECTOR, NOT THE FUSE) PRIOR TO PROGRAMMING. When programming is complete, reconnect the blower motor. 12. 1997 VEHICLES REQUIRE REPROGRAMMING BE DONE USING A TECH 2. OBD II vehicle calibration size and complexity will require more memory than the Tech 1 has available. Tech 2 will be an essential tool in the first quarter of 1996 containing limited 1996 applications and updates. 13. STG HAS ISSUED BULLETINS (# 53-65-04 and # 53-65-05 - (SEE CHART EXCERPTED FROM 53-65-05 FOR USE AS A QUICK REFERENCE GUIDE), DEVELOPED QUICK REFERENCE GUIDES (P/N SPSCARD-1 AVAILABLE THROUGH YOUR LOCAL GM TRAINING CENTER), PRODUCED CPT VIDEOS (CPT # 56010.00-B), HAD PULSAT BROADCASTS, AND OFFERS GM TRAINING CENTER CLASSROOM COURSES. As you work through reprogramming, keep the above-mentioned material in mind as resources to assist you if difficulty is encountered. As always, the Techline Customer Support Center (1-800-828-6860 English, 1-800-503-3222 French) is always available to assist the technician with any situation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming > Page 5995 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming > Page 5996 SPS/EEPROM Programming 1993 to current Reprogrammable Vehicles Note: If programming a new control module you must request info from the new control module first. Battery voltage should be checked and at full charge before reprogramming takes place. System to be programmed should NOT be connected to a battery charger. Incorrect voltage could cause programming and/or control module failure. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 536505 > Oct > 95 > SPS/EEPROM - Programming Chart PROM - Programmable Read Only Memory: All Technical Service Bulletins SPS/EEPROM Programming Chart File In Section: 6E - Engine Fuel & Emission Bulletin No.: 53-65-05 Date: October, 1995 Subject: Chart to Assist Technician with SPS/EEPROM Programming Models: 1995-96 Passenger Cars and Trucks This bulletin is being issued to assist technicians with the reprogramming of vehicles. The following chart was developed to be used by technicians that are familiar with the Techline terminals, Tech 1 and all of its adapters: IMPORTANT If programming a new control module, you must request information from the new control module first. Battery voltage must be between 11 and 14 volts. System to be programmed should NOT be connected to a battery charger. Incorrect voltage could cause programming and/or control module failure. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 536505 > Oct > 95 > SPS/EEPROM - Programming Chart > Page 6001 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Technical Service Bulletins for PROM - Programmable Read Only Memory: > 536505 > Oct > 95 > SPS/EEPROM - Programming Chart > Page 6002 Programming Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 99-06-04-053 > Nov > 99 > PROM - Powertrain Control Module Reprogramming PROM - Programmable Read Only Memory: All Technical Service Bulletins PROM - Powertrain Control Module Reprogramming File In Section: 06 - Engine/Propulsion System Bulletin No.: 99-06-04-053 Date: November, 1999 INFORMATION Subject: Powertrain Control Module (PCM) Reprogramming (Do Not Reprogram Using the Same Download Files as Those Already Present in The Control Module) Models: 1990-2000 Passenger Cars and Trucks with Reprogrammable PCM It is strongly recommended to NOT reinstall the same software and/or calibration download file(s) into the powertrain control module as those that are already present in the PCM. There is no technical reason that the download files inside the PCM would ever become corrupted after the control module had previously been successfully programmed. A P0601 (Control Module Read Only Memory) Diagnostic Trouble Code would set in memory and the MIL would be illuminated if the controller memory became corrupted. The Techline Information System 2000 (TIS 2000) PC, combined with vehicle information gained through the Tech 2, can determine when an attempt to reprogram a PCM using the same download files (as those already in the control module) is being requested. If this is attempted, the TIS 2000 PC currently displays the following message: Notice: THE CALIBRATION SELECTED IS THE CURRENT CALIBRATION IN THE CONTROL MODULE. PROGRAMMING WITH THE SAME DOWNLOAD FILES IS NOT AN EFFECTIVE REPAIR. SELECT ( YES ) TO CONTINUE PROGRAMMING THE CONTROL MODULE,OR ( NO ) TO CANCEL. Effective in the first quarter of 2000, the TIS 2000 PC will indicate: Important: THE CALIBRATION SELECTED IS ALREADY THE CURRENT CALIBRATION IN THE CONTROL MODULE. REPROGRAMMING WITH THE SAME DOWNLOAD FILE IS NOT ALLOWED. Certain learned values, such as: (but not limited to) ^ fuel trim (previously known as block learn memory), ^ IAC learned position in various park/neutral and air conditioning on/off combinations, ^ certain OBDII diagnostic thresholds, ^ automatic transmission shift adapts will revert back to their unlearned starting point values after a reprogramming event occurs. It is feasible that the engine or transmission might temporarily operate differently after a reprogramming event, until these values are re-learned. Relearning occurs while operating the vehicle through normal driving routines. If the same download files are simply reinstalled, any changes noticed in engine operation will likely disappear in a short amount of time and/or driving distance. Reprogramming the control module with the same download files that already exist in the module will only accomplish a warranty claim for a non-effective repair, and a likely comeback. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter PROM - Programmable Read Only Memory: All Technical Service Bulletins PROM - Reprogram Using Off Board Program Adapter File In Section: 6E - Engine Fuel & Emission Bulletin No.: 73-65-13 Date: March, 1997 INFORMATION Subject: Reprogramming Capability using the Off Board Programming Adapter Models: 1993-97 Passenger Cars and Trucks (Applicable Reprogrammable Vehicles) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 6012 The General Motors vehicles contain Electronically Reprogrammable Devices (i.e. PCM, VCM, ECM). These vehicles cannot be programmed through PROM replacement, however service programming capability is available through the Tech 1/1A, Tech 2 and Techline terminals via direct or remote programming. The Environmental Protection Agency (EPA) has requested that all new vehicle manufacturers ensure their dealers/retailers are aware that they are responsible for providing customers access to reprogramming services at a reasonable cost and in a timely manner. Although programming of controllers has become a common service practice at GM dealers/retailers, the EPA has received reports from consumers and the aftermarket repair industry that they were unable to purchase a new (programmed) Electronically Reprogrammable Device (ERD) over-the-counter. As a result, on August 1, 1995, the Federal Government issued a regulation requiring all manufacturers to make available reprogramming to the independent aftermarket by December 1, 1997. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 6013 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 6014 Today, the Off Board Programming Adapter (OBPA) is used to reprogram ERD's sold over-the-counter. For all practical purposes, the OBPA takes the place of the vehicle when the vehicle is not available. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 6015 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 6016 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 6017 The list of dealerships/retailers currently own the OBPA (see Attachments 1 - 3). These locations are equipped to provide over-the-counter preprogrammed ERD's. The hardware required to perform reprogramming in addition to the OBPA is a Techline terminal, Tech 1/1A and associated cables and adapters. THE TECH 2 SHOULD NOT BE USED WITH THE OBPA AT THIS TIME BECAUSE OF INADEQUATE OBPA GROUNDING. The current OBPA can support reprogramming on all late model General Motor's vehicles except: ^ Premium V-8's ^ 1996 Diesel Truck ^ Cadillac Catera Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 736513 > Mar > 97 > PROM - Reprogram Using Off Board Program Adapter > Page 6018 ^ All 1997 programmable vehicles (requires use of the Tech 2) A modification to the OBPA is being offered by Kent-Moore to support these additional vehicles and to allow reprogramming using the Tech 2. The revisions to the OBPA for the Tech 2 is very important as the Tech 2 is the only tool used for service programming for 1997 and future vehicles. To have the modifications performed, contact Kent-Moore at (800) 345-2233. The revisions (part number J 41207 REV-C) are free of charge for GM dealerships/retailers. A dealership/retailer can purchase the OBPA by contacting Kent-Moore (part number J 41207-C). Support on how to use the OBPA is provided by the Techline Customer Support Center (TCSC) at (800) 828-6860 (English) or (800) 503-3222 (French). If you need to purchase an OBPA and/or cable, contact Kent-Moore at (800) 345-2233. The OBPA retails for $695.00 (includes all revisions 1-4) under part number J 41207-C. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming PROM - Programmable Read Only Memory: All Technical Service Bulletins SPS/FLASH EPROM Programming File In Section: 6E - Engine Fuel & Emission Bulletin No.: 53-65-08 Date: January, 1996 INFORMATION Subject: SPS/FLASH EPROM Programming Models: 1993-96 Passenger Cars and Trucks Applicable Reprogrammable Vehicles This bulletin is being issued to assist technicians in reprogramming vehicles and should be used in conjunction with instructions provided on your Techline Terminal and in your Techline Terminal User's Manual. THE TECHLINE TERMINAL (T-20, T-50, T-60) HAS BEEN ABLE TO DO 1996 VEHICLE PROGRAMMING THROUGH THE DIRECT METHOD SINCE 1996 VEHICLES HAVE BEEN AVAILABLE IN THE DEALERSHIPS/RETAIL FACILITIES. THE TECHLINE CD-ROM TITLED DISC 13 CONTAINS THE SOFTWARE NEEDED TO PROGRAM ALL 1996 VEHICLES WITH A TECH 1 (REMOTE PROGRAMMING METHOD). SPS Tips 1. BATTERY VOLTAGE SHOULD BE CHECKED. A FULLY CHARGED BATTERY IS NECESSARY BEFORE REPROGRAMMING TAKES PLACE. THE VEHICLE BATTERY SHOULD NOT BE CONNECTED TO A BATTERY CHARGER DURING A PROGRAMMING EVENT INCORRECT VOLTAGE COULD CAUSE PROGRAMMING AND/OR CONTROL MODULE FAILURE. During programming, the control module depends on the battery as its sole source of power. Also during programming, the vehicle's components (i.e. blower motor) are set to a default mode which may be turned on, placing additional draw on the vehicle's battery. If the voltage goes outside the specified range (11 to 14 volts) the controllers and the Techline equipment will stop communicating. If this happens, it could cause the control module to become inoperable and require replacement. 2. CHECK THE INTEGRITY OF THE TECH 1 CABLES, MAKE SURE THEY ARE NOT FRAYED, BROKEN OR TWISTED. Loss of communication for any reason will require additional time in completing the reprogramming event. 3. IF USING A TECH 1, YOUR MASS STORAGE CARTRIDGE (MSC) MUST BE UPDATED TO REFLECT THE MOST CURRENT UPDATE OFFERED ON THE TECHLINE CD-ROM. DISC 13, 1995 WAS THE FIRST CD-ROM THAT HAD REMOTE PROGRAMMING SUPPORT If your MSC is not updated to reflect the current software version on the Techline Terminal, in some situations the software will not be capable of interpreting the information that is requested from the vehicle. 4. T-100 TERMINALS (CAMS) ARE NOT CAPABLE OF PROGRAMMING OBD II VEHICLES THROUGH THE DIRECT METHOD. A TECH 1 MUST BE USED (REMOTE METHOD) WHEN REPROGRAMMING WITH A T-100. The T-100 terminals communicate with vehicles through a DLC (ALDL) card and cable found within the T-100's computer. The DLC (ALDL) card is not capable of communicating at the new baud rate used with OBD II. 5. PROGRAMMING IS NOT NEEDED IF THE CURRENT CALIBRATION IS THE SAME AS THE SELECTED CALIBRATION. 6. IF PROGRAMMING A NEW CONTROL MODULE, YOU MUST REQUEST INFORMATION FROM THE NEW CONTROL MODULE. The security information that is needed for a control module to be programmed is stored in the new control module. The security information must be requested from the control module to be programmed. At that point, the control module can be successfully programmed. This requesting of security information takes place in both the direct and remote methods. The request is automatic when using the direct method. Looking at the calibration stored in the old controller may be helpful in selecting the calibration from the CD-ROM for the new controller. 7. WHEN PROGRAMMING OBD II VEHICLES WITH A TECH 1 (REMOTE PROGRAMMING METHOD), A VEHICLE INTERFACE MODULE (VIM) IS REQUIRED. The VIM allows the Tech 1 to communicate with the OBD II vehicles. The VIM is necessary for all other Tech 1 diagnostics on OBD II vehicles. VIMs are no longer on backorder. If you are interested in obtaining additional VIMs, call 1-800-GM-TOOLS and ask for VIM kit part number 7000041. 8. DISCONNECT THE TECH I AND VIM FROM THE VEHICLE BETWEEN RETRIEVING DATA AND PROGRAMMING THE VEHICLE. If the VIM remains powered up after data is requested, a communication problem may result when the reprogramming function is performed. 9. WHEN CONNECTING THE TECH 1 TO A TECHLINE TERMINAL (EXCEPT T-100 CAMS), ALWAYS CONNECT THE FLAT GRAY R5232 CABLE FIRST AND THEN THE POWER ADAPTER. FAILURE TO DO SO COULD RESULT IN A LOSS OF INFORMATION Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming > Page 6023 STORED ON THE TECH 1. When power is turned on to the Tech 1, it looks for the RS232 connection. If it does not see the connection, the Tech 1 in some cases, will erase the information stored for download. 10. DO NOT DISCONTINUE OR INTERRUPT THE PROGRAM LOADING PROCESS TO THE VEHICLE. This will result in a programming error and could prevent the Electronic Control Module (ECM) from functioning properly. 11. AFTER PROGRAMMING IS COMPLETE, PRESS "EXIT". MAKE SURE THE KEY IS CYCLED OFF FOR APPROXIMATELY 10 SECONDS THEN BACK ON. Some vehicles will lose component settings (PMC/IAC Valve). Cycling the key off two times (Off for 30 seconds, On for 10 then repeat a second time) will allow for resetting of the components. Start the vehicle to ensure programming was successful. FOR CADILLAC VEHICLES ONLY a. DUE TO OTHER MODULES ON THE DATA LINE TRYING TO COMMUNICATE WITH THE ECM DURING PROGRAMMING, SOME COMMUNICATION CODES MAY BE SET After programming is complete, clear any codes and verify they do not reset. b. TO HELP MINIMIZE BATTERY DRAW DURING ECM PROGRAMMING, DISCONNECT THE BLOWER MOTOR (AT THE CONNECTOR, NOT THE FUSE) PRIOR TO PROGRAMMING. When programming is complete, reconnect the blower motor. 12. 1997 VEHICLES REQUIRE REPROGRAMMING BE DONE USING A TECH 2. OBD II vehicle calibration size and complexity will require more memory than the Tech 1 has available. Tech 2 will be an essential tool in the first quarter of 1996 containing limited 1996 applications and updates. 13. STG HAS ISSUED BULLETINS (# 53-65-04 and # 53-65-05 - (SEE CHART EXCERPTED FROM 53-65-05 FOR USE AS A QUICK REFERENCE GUIDE), DEVELOPED QUICK REFERENCE GUIDES (P/N SPSCARD-1 AVAILABLE THROUGH YOUR LOCAL GM TRAINING CENTER), PRODUCED CPT VIDEOS (CPT # 56010.00-B), HAD PULSAT BROADCASTS, AND OFFERS GM TRAINING CENTER CLASSROOM COURSES. As you work through reprogramming, keep the above-mentioned material in mind as resources to assist you if difficulty is encountered. As always, the Techline Customer Support Center (1-800-828-6860 English, 1-800-503-3222 French) is always available to assist the technician with any situation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming > Page 6024 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 536508 > Jan > 96 > SPS/FLASH EPROM - Programming > Page 6025 SPS/EEPROM Programming 1993 to current Reprogrammable Vehicles Note: If programming a new control module you must request info from the new control module first. Battery voltage should be checked and at full charge before reprogramming takes place. System to be programmed should NOT be connected to a battery charger. Incorrect voltage could cause programming and/or control module failure. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 536505 > Oct > 95 > SPS/EEPROM - Programming Chart PROM - Programmable Read Only Memory: All Technical Service Bulletins SPS/EEPROM Programming Chart File In Section: 6E - Engine Fuel & Emission Bulletin No.: 53-65-05 Date: October, 1995 Subject: Chart to Assist Technician with SPS/EEPROM Programming Models: 1995-96 Passenger Cars and Trucks This bulletin is being issued to assist technicians with the reprogramming of vehicles. The following chart was developed to be used by technicians that are familiar with the Techline terminals, Tech 1 and all of its adapters: IMPORTANT If programming a new control module, you must request information from the new control module first. Battery voltage must be between 11 and 14 volts. System to be programmed should NOT be connected to a battery charger. Incorrect voltage could cause programming and/or control module failure. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 536505 > Oct > 95 > SPS/EEPROM - Programming Chart > Page 6030 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > All Other Service Bulletins for PROM - Programmable Read Only Memory: > 536505 > Oct > 95 > SPS/EEPROM - Programming Chart > Page 6031 Programming Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Technical Service Bulletins > Page 6032 PROM - Programmable Read Only Memory: Service Precautions A PROM is a sensitive electronic part and must be handled with care. If the connector terminals (pins) on the bottom of the PROM are exposed, avoid touching them. Pins can be broken easily, and the PROM can be damaged by static electric discharge. Follow these guidelines when replacing a PROM: ^ Disconnect the battery ground cable before removing a PROM. Reconnect the cable after the new PROM is installed. ^ DO NOT try to remove a PROM from its plastic PROM carrier. ^ Note the direction in which the original PROM and its carrier were installed in the ECM, and install the replacement PROM in the same direction. Most PROM's are marked with a notch at one end for orientation. Many PROM's can be installed in a reversed direction, which will destroy the PROM when power is applied. CAUTION: A PROM can be damaged by static electric discharge. Avoid damage as follows: ^ DO NOT remove a PROM from its packing material until you are ready to install it. DO NOT hold a PROM by its pins. ^ Before entering a vehicle to remove or replace a PROM, touch an exposed metal part of the vehicle to discharge any static charge from your body or use anti-static wrist straps. ^ Avoid sliding across upholstery or carpeting when removing or installing a PROM. If this is not possible, touch an exposed metal part of the vehicle with your free hand before removing a PROM or installing a new one in its socket in the ECM. ^ When available, use an antistatic grounding strap attached to your wrist and clipped to a metal part of the vehicle body to prevent static charges from accumulating. Antistatic, conductive floormats are also available. ^ For some vehicles, it may be desirable to remove the ECM when replacing the PROM. ^ NOTE: See POWERTRAIN MANAGEMENT / SERVICE PRECAUTIONS / VEHICLE DAMAGE WARNINGS / ELECTRICAL PRECAUTIONS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index PROM - Programmable Read Only Memory: Application and ID Introducing the GM PROM Cross Reference Index This PROM cross reference index provides tables that let you use a PROM identification (ID) code to identify the PROM installed in the engine control module (ECM) on most GM vehicles. The code can be either - or both - the internal "scan ID" code or the external PROM code. From the PROM identification, you can find the part number of the PROM and trace the PROM history to determine if any revised PROM's have been issued to supersede the one in the vehicle. The PROM history for a specific vehicle lists a succession of superseding PROM's ending with the most recent PROM released as a service part for the vehicle. PROM's that were released as service parts and explained in a technical service bulletin (TSB) are listed with a description of why the PROM was issued. In most cases, the applicable TSB also is referenced. This index lists ECM PROM's for the 1980-95 vehicles. It does not contain ID codes and part numbers for all PROM's used in all GM vehicles. NOTE: GM flash PROM's (EEPROM's) can only be updated at GM Dealerships with factory-supplied equipment. These cars will not display a PROM ID. By following the steps outlined below, you can use the PROM index to determine if the problem you are diagnosing can possibly be corrected by installing a revised PROM. The PROM index tables are organized by model year, engine displacement, and engine code (the eighth digit of the Vehicle Identification Number). The table columns are arranged as shown below: Example of Table Column Arrangement SCAN PROM PROM PART SUPERSEDING TSB REFERENCE ID CODE (BCC) NUMBER ID PART NUMBER NUMBER (1) (2) (3) (4) (5) .............................................................................................................................................................. ........................................................................ 9461 8958 AMU 16058955R 8290 01228290 86194 Column 1, SCAN ID: The scan ID is the internal PROM identification number transmitted on the ECM data stream and displayed by the scanner as PROM ID. The PROM records for each year and engine are listed numerically by this scan ID. Column 2, PROM CODE: These are the numbers and letters marked on the top of the PROM itself. The numbers are often referred to as the "external PROM ID." The letters are often called the "broadcast code." Together they are the external PROM code. Column 3, PROM P/N: This is the GM part number for the PROM identified by the codes in columns 1 and 2. Column 4, SUPERSEDING ID PROM PART NUMBER: Use the superseding scan ID to locate the newer PROM in the table. If the scan ID for the superseding PROM is not known, the PROM broadcast code is listed here. If the PROM is superseded by a newer PROM, that part number is listed here. Column 5, TSB REFERENCE NUMBER The TSB NUMBER column identifies the original TSB that released this PROM for service. Whenever possible you should refer to the TSB for additional information before changing a PROM. The bulletin may list other parts that must be installed when the PROM is changed, or it may provide additional troubleshooting information. To find a TSB, see Reading Technical Service Bulletins. See: Reading Technical Service Bulletins This will display all the TSB's for that particular vehicle. EXPANDED FOOTNOTES Here you will find SUPERSEDING SCAN ID, PROM PART NUMBERS, symptoms and additional parts that need to be replaced when servicing the PROM. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6035 PROM - Programmable Read Only Memory: Application and ID Additional PROM Information New ECM PROMs for GM vehicles may be released for service at any time. The information in this system is accurate to the best of the publisher's knowledge and the publication date of the disk. Before ordering a PROM, consult with a GM parts and service dealer to verify the latest part number information. Scanner PROM ID information for earlier-model vehicles (1980-83) is less complete than for later models. To accurately identify PROM's in earlier vehicles, it may be necessary to check the external PROM code marked on the PROM. General Motors has often recommended that dealership technicians check the PROM history of a vehicle and install the most recent PROM revision before performing other diagnostic operations. Each succeeding PROM revision for a specific vehicle includes all previous revisions. Therefore, whenever you consider changing a PROM, review the entire PROM history to see if any revision covered the current driveability problem. Installing the most recent PROM revision may be impractical however for an independent service facility, particularly if the latest PROM revision does not address the specific driveability problem of the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6036 PROM - Programmable Read Only Memory: Application and ID PROM/MEMCAL Identification Marks File In Section: 6E - Engine Fuel & Emission Bulletin No.: 44-65-01 Date: October, 1994 Subject: New PROM/MEMCAL Identification Markings Models: 1995 and Prior Passenger Cars and Trucks Note: For the purposes of this document, the terms PROM and MEMCAL will be used interchangeably. To simplify identification of service PROMs. a new external marking format will be implemented. Parts manufactured after Sept. 1994 will feature these new markings. This change will place the full 8-digit service part number on the PROM, in place of the old 4-digit "EXTERNAL ID" number. In the past, parts and service personnel could not identify a PROM without using a cross-reference table that matched external IDs and service numbers. In the future, the cross-reference table will not be required for PROMs; parts will be ordered directly from the number appearing on the PROM. However, the label will retain the broadcast code alpha characters to allow continued use of cross-reference charts, if so desired. Old Marking Format: New Marking Format: ^ Ordering the above PROM from the old marking format would require using a cross-reference chart to determine a service part number, based on the BROAD CAST CODE and EXTERNAL ID NUMBERS. ^ To order from the new format, simply combine the 2nd and 3rd lines to form an 8-digit part number that can be directly ordered from SPO (number 16134624 in the above example). As these changes are phased into the parts inventory, it should be noted that dealers will continue to see parts with both formats for some time in the future. This is because: ^ Millions of vehicles have already been built with the old format. ^ SPO has existing stock of MEMCALs and PROMs with the old format. ^ PROMS with 7-digit part numbers (representing less than 10% of current part numbers) will continue to use the old format. The 7-digit part numbers are easily identified because they always begin with "122xxxx". Due to manufacturing processes, more than one 8-digit part number may appear on a MEMCAL. In this event, service personnel should use the label on the exterior cover of the MEMCAL assembly. To avoid confusion, only the service label will include the BROAD CAST CODE, consisting of letter characters (I.E., ARCL). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6037 CHANGES TO MEMCAL/PROM LABELING FORMATS ^ MEMCALs may use either INK-JET or ADHESIVE labels, as shown. ^ PROMs will always use ADHESIVE labels with the same format as shown for MEMCALs. These changes will become effective on parts manufactured after 10/94. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6038 PROM - Programmable Read Only Memory: Application and ID Reading Technical Service Bulletins Always read any Technical Service Bulletins (TSB's) referenced before replacing a PROM. Service bulletins list parts that must be installed when a PROM is changed, and provide information on trouble codes, troubleshooting and driveability problems for which the PROM was released. To find applicable TSB's: Complete TSB Listing 1. Hold down right mouse button and select "Vehicle" in the "Pull Right Menu". 2. Select the TSB ICON. 3. Select "All Technical Service Bulletins by Number, Date, and Title". 4. Select "Sort by Number", "Sort by Date", or "Sort by Title". 5. Scroll up or down to find the desired TSB. PROM TSB Listing Only 1. Hold down right mouse button and select "Technical Service Bulletins" in the "Pull Right Menu". 2. Select "All Technical Service Bulletins for PROM - Programmable Read Only Memory". 3. Select "Sort by Number", "Sort by Date", or "Sort by Title". 4. Scroll up or down to find the desired TSB. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6039 PROM - Programmable Read Only Memory: Application and ID Expanded Footnotes Footnotes 1 Thru 50 [1] Also needs EGR P/N 1706739. [2] Also requires EGR P/N 17111295. [3] Requires Throttle Body service P/N 17067142, EGR valve service P/N 17067111, Injector service kit P/N 17067976. [4] Requires Throttle Body service P/N 17067142, EGR valve service P/N 17067107, Injector service kit P/N 17067976. [5] Requires Throttle Body service P/N 17067144, EGR valve service P/N 17067110, Injector service kit P/N 17067976. [6] PROM I.D. 7080 KJ is also acceptable for PROM I.D. 5853 KJ only. Requires Throttle Body service P/N 17067144, EGR valve service P/N 17067108 (FED), 17067144 (CAL), Injector service kit P/N 17067976. [7] Required Throttle Body service P/N 17067142, EGR valve service P/N 17067107 (FED), 17068210 (CAL), Injector service kit P/N 17067976. [8] Requires Throttle Body service P/N 17068019, EGR valve service P/N 17067109, Injector service kit P/N 17067976. [9] For Federal - Use 01226047 (PROM CODE 7654 BKW). For California - Use 01226049 (PROM CODE 7665 BKY). [10] For Federal - Use 01226054. For California - Use 01226056 [11] For Federal - Use 01226055. For California - Use 01226057. [12] For Federal - Use 01226046 (PROM CODE 7648 BKU). For California - Use 01226049 (PROM CODE 7665 BKY). [13] For federal - Use 01226046 (PROM CODE 7648 BKU). For California - Use 01226048 (PROM CODE 7659 BKX). [14] ECM may have been replaced by service ECM P/N 16019710 (1225500). [15] ECM may also be 16018161. ECM may also have been replaced by service ECM P/N 16018000 (1225330). [16] ECM may also be 16018201. ECM may also have been replaced by service ECM P/N 16018000 (1225330). [17] ECM may also be 16018211. ECM may have been replaced by service ECM P/N 16018000 (1225330). [18] ECM may also be 16023761. ECM may have been replaced by service ECM P/N 16018000 (1225330). [19] ECM may also be 16018101. ECM may have been replaced by service ECM P/N 16018000 (1225330). [20] For 2-board ECM only. [21] May need EGR valve P/N 17079563. Original equipment P/N 16029014. [22] Original equipment PROM P/N 16017094, now 16025254 [23] Original equipment PROM P/N 16017224, now 16025264. [24] Also needs EGR valve P/N 17079013. Original equipment PROM P/N 16030034 (PROM ID: BOH). [25] Requires kit P/N 25522748 containing: Wiring harness jumper P/N 12043500, Relay P/N 25522747, Foam P/N 25522723, EGR P/N 17079799. [26] Needs EGR valve P/N 17079818. [27] For (MY7) - Use 01226473 (SCAN I.D. = 3941). For (M19) - Use 01226474 (SCAN I.D. = 3951). [28] For (MY7) or (M19, C60) - Use 01226473 (SCAN I.D. = 3941). For (M19) - Use 01226474 (SCAN I.D. = 3951). [29] ECM may also be 16023561(M5), or 16033061(M4 with A/C). [30] For F62 axle - Use 01226441 (SCAN I.D. = 3622). For F17 axle - Use 01226439 (SCAN I.D. = 3332). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6040 [31] For one_board ECM only. [32] Requires Thermac Sensor P/N 8997916. [33] For Federal - Use 01227729 (SCAN I.D. = 7729). For California - Use 01227728 (SCAN I.D. = 7728). [34] Use 01227629 (SCAN I.D. = 7629) only to resolve surge or chuggle. [35] Use 01227381 (SCAN I.D. = 7381) only to resolve chuggle. [36] Use 01227386 (SCAN I.D. = 7386) only to resolve chuggle. [37] Retrofit PROM - Does not supersede the regular replacement service PROM. To be used only as required to resolve cases of chuggle. [38] Retrofit PROM - Supersedes all previous service PROM part numbers. To be used as both the regular service replacement (PROM-damaged or defective), and to resolve cases of chuggle. [39] Retrofit PROM - Supersedes all previous service PROM part numbers. To be used as both the regular service replacement (PROM-damaged or defective), and to resolve cases of chuggle, detonation, or flatness. [40] Retrofit PROM - Does not supersede the regular replacement service PROMS. To be used only as required to resolve cases of chuggle, detonation, or flatness. [41] Need EGR valve P/N 17111577 (Federal only). [42] For use with P215/65 tires - use 01228290 (SCAN I.D. = 8290). For use with P235/60, P245/50 tires - use 01228291 (SCAN I.D. = 8291). [43] For use with P215/65 tires - use 01228292 (SCAN I.D. - 8292). For use with P235/60, P245/50 tires - use 01228293 (SCAN I.D. = 8293). [44] Use 16143570 (SCAN I.D. = 3531) for hot hard restart (Requires Fuel Pump P/N 25115764, Fuel Sender P/N 25093526). Use 16143459 (SCAN I.D. = 3571) for Code 42, Spark Knock, High Idle. [45] Use 16143455 (SCAN I.D. = 3511) for hot hard restart (Requires Fuel Pump P/N 25115764, Fuel Sender P/N 25093526). Use 16143453 (SCAN I.D. = 3501) for Code 42, Spark Knock, High Idle. [46] Use 16143575 (SCAN I.D. = 3541) for hot hard restart (Requires Fuel Pump P/N 25115764). Use 16143460 (SCAN I.D. = 3581) for Code 42, Spark Knock, High Idle. [47] Use 16143580 (SCAN I.D. = 3551) for hot hard restart (Requires Fuel Pump P/N 25115764). Use 16143462 (SCAN I.D. = 3591) for Code 42, Spark Knock, High Idle. [48] Use 16143457 (SCAN I.D. = 3521) for hot hard restart (Requires Fuel Pump P/N 25115925, Fuel Sender P/N 25092778). Use 16143466 (SCAN I.D. = 3481) for Code 42, Spark Knock, High Idle. [49] Use 16143452 (SCAN I.D. = 3491) for hot hard restart (Requires Fuel Pump P/N 25115925, Fuel Sender P/N 25092778). Use 16143463 (SCAN I.D. = 3451) for Code 42, Spark Knock, High Idle. [50] Needs air injection service kit (P/N 10115773) and new vehicle emission control label. Footnotes 51 Thru 100 [51] Must be ordered with service kit P/N 10115773. [52] With this PROM installed, use 1987-88 2.8L speed density engine driveability and emissions manual. [53] PROM update eliminates MAF sensor, replacing it with a speed density system. With a 1990 or earlier primary cartridge, I.D. vehicle on scanner as a 1989 model (VIN = K-1-W). [54] For 2WD use 16120099 (SCAN I.D. = 9941). For 4WD use 16120109 (SCAN I.D. = 9901). [55] For 2.73 (GU2) Axle use 16120077 (SCAN I.D. = 9891). For 3.08 (GU4) Axle use 16120082 (SCAN I.D. = 9901). For 3.42 (GU6) and 3.73 (GT4) Axles use 16120086 (SCAN I.D. = 9911). [56] For 2WD use 16120042 (SCAN I.D. = 9991). For 4WD use 16120129 (SCAN I.D. = 0011). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6041 [57] Needs accelerator pump check ball spring P/N 17069583. [58] For false Code 44 on long coast down, use retrofit service PROM 01228486 AAND 1050. For regular service replacement, use PROM 16062797 AAND 2798. [59] For false Code 44 on long coast down, use retrofit service PROM 01228487 AANF 1052. For regular service replacement, use PROM 16062801 AANF 2802. [60] USE 16143545 (SCAN I.D. = 3461) For hot hard restart (Requires Fuel Pump P/N 25115764, Fuel Sender P/N 25093744). Use 16143465 (SCAN I.D. = 3471) for Code 42, Spark Knock, High Idle. [61] With this PROM installed, use 1987-88 2.8L speed density engine driveability and emissions manual. [62] For use with model C1 Trucks - Use 16121162 (SCAN I.D. = 3511). For use with model C2, K, K2, AND K1000 Trucks - use 16121166 (SCAN I.D. = 3521). [63] Also requires installation of new EGR valve package P/N 17112238 (Contains EGR valve P/N 17090078 and a gasket). [64] Use 16181863 (SCAN I.D. = 0844) for cold start stall. Use 16181859 (SCAN I.D. = 0834) only if required to solve both cold start stall and chuggle. [65] Use 16181871 (SCAN I.D. = 0864) for cold start stall. Use 16181867 (SCAN I.D. = 0854) only if required to solve both cold start stall and chuggle. [66] Use 16165848 (SCAN I.D. = 5614) for cold start stall. Use 16165843 (SCAN I.D. = 5624) only if required to solve both cold start stall and chuggle. [67] Do not rely on the scanner ID to determine which PROM is in a vehicle. Look at the BCC on the PROM to be sure. Do not confuse with some 1991 models with a 2.84 axle ratio and a Federal emissions pkg which used scanner ID 5644 but had a BCC of AWJD. [68] This PROM may have a negative impact on fuel economy. [69] Cannot be used on vehicles that do not have digital EGR valves. [70] Use 16165839 (SCAN I.D. = 5634) for cold start stall. Use 16165829 (SCAN I.D. = 5644) only if required to solve both cold start stall and chuggle. [71] Use 16181883 (SCAN I.D. = 0894) for cold start stall. Use 16181875 (SCAN I.D. = 0874) only if required to solve both cold start stall and chuggle. [72] Use 16181887 (SCAN I.D. = 0904) for cold start stall. Use 16181879 (SCAN I.D. = 0884) only if required to solve both cold start stall and chuggle. [73] This PROM may have a negative impact on fuel economy. [74] PROM can only be used with ECM P/N 16144288. [75] Make certain the vehicle has been updated with previously attempted service fixes as follows: EGR valve P/N 17090156 (stamped on valve) 17112373 (GMSPO kit), PCV valve P/N 25098542, ESC module P/N 16175099 (BCC=BARC). [76] For vehicles with sleeve bearing engines. [77] Combination detonation and neutral gear rattle PROM available. [78] Needs ESC P/N 16175099. [79] Model 2DDM Transmissions - Check dealer records to see if the torque converter has already been replaced with P/N 8650935 (Tagged BCC: DGAF). Trans. with torque converters with P/N 8656959 (Tagged BCC: DG5F) need to replace it with P/N 8650935. [80] For dedicated natural gas vehicles. Order with kit P/N 12545589 unless the only problem is idle fluctuation. [81] For chuggle at 40-45 condition, use PROM only. For tip-in hesitation only, use EGR valve only - P/N 17078431. For cold driveability hesitation, use both PROM and EGR. [82] Requires supplementary tune-up label, spark bypass relay kit P/N 14086983, spark plugs P/N 5614009, sun visor starting label P/N 14085150. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6042 Also, remove and discard fuse labeled "crank" from fuse BLK #2 position (3 Amp. Fuse). [83] Manual transmission cars should also be updated with the clutch anticipate switch per dealer service bulletin number. 91-472-7C. [84] Cold driveability, use with PROM 0051 AAF (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067111, INJECTOR SERVICE KIT P/N 17067976. [85] Cold driveability, use with PROM 0050 AAF (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067111, INJECTOR SERVICE KIT P/N 17067976. [86] Exhaust noise (requires catalytic converter), cold driveability, use with PROM 5884 BH (G057). REQUIRES THROTTLE BODY SERVICE P/N 17068019, EGR VALVE SERVICE P/N 17067109, INJECTOR SERVICE KIT P/N 17067976. [87] Exhaust noise (requires catalytic converter), cold driveability, use with PROM 5869 BH (G057). REQUIRES THROTTLE BODY SERVICE P/N 17068019, EGR VALVE SERVICE P/N 17067109, INJECTOR SERVICE KIT P/N 17067976. [88] Exhaust noise (requires catalytic converter), cold driveability, use with PROM 5779 KB (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067144, EGR VALVE SERVICE P/N 17067110, INJECTOR SERVICE KIT P/N 17067976. [89] Exhaust noise (requires catalytic converter), cold driveability, use with PROM 5778 KB (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067144, EGR VALVE SERVICE P/N 17067110, INJECTOR SERVICE KIT P/N 17067976. [90] Cold driveability, use with PROM 5854 KJ (G057). PROM I.D. 7080 KJ IS ALSO ACCEPTABLE FOR PROM I.D. 5853 KJ ONLY. REQUIRES THROTTLE BODY SERVICE P/N 17067144, EGR VALVE SERVICE P/N 17067108 (FED), 17067144 (CAL), INJECTOR SERVICE KIT P/N 17067976. [91] Cold driveability, use with PROM 5853 KJ (G057). PROM I.D. 7080 KJ IS ALSO ACCEPTABLE FOR PROM I.D. 5853 KJ ONLY. REQUIRES THROTTLE BODY SERVICE P/N 17067144, EGR VALVE SERVICE P/N 17067108 (FED), 17067144 (CAL), INJECTOR SERVICE KIT P/N 17067976. [92] Cold driveability, use with PROM 5861 KK (G057). REQUIRED THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067107 (FED), 17068210 (CAL), INJECTOR SERVICE KIT P/N 17067976. [93] Cold driveability, use with PROM 5860 KK (G057). REQUIRED THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067107 (FED), 17068210 (CAL), INJECTOR SERVICE KIT P/N 17067976. [94] Exhaust noise (requires catalytic converter), cold driveability, use with PROM 5786 LW (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067107, INJECTOR SERVICE KIT P/N 17067976. [95] Exhaust noise (requires catalytic converter), cold driveability, use with PROM 5785 LW (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067107, INJECTOR SERVICE KIT P/N 17067976. [96] Cold driveability, use with PROM 7088 LY (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067111, INJECTOR SERVICE KIT P/N 17067976. [97] Cold driveability, use with PROM 7087 LY (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067111, INJECTOR SERVICE KIT P/N 17067976. [98] Chuggle at 40-45 mph, cold driveability hesitation. FOR CHUGGLE AT 40-45 CONDITION, USE PROM ONLY. FOR TIP-IN HESITATION ONLY, USE EGR VALVE ONLY - P/N 17078431. FOR COLD DRIVEABILITY HESITATION, USE BOTH PROM AND EGR. [99] Driveability correction for heavy chuggle. REQUIRES KIT P/N 25522748 CONTAINING: WIRING HARNESS JUMPER P/N 12043500, RELAY P/N 25522747, FOAM P/N 25522723, EGR P/N 17079799. [100] Cold startability adjustment. REQUIRES SUPPLEMENTARY TUNE-UP LABEL, SPARK BYPASS RELAY KIT P/N 14086983, SPARK PLUGS P/N 5614009, SUN VISOR STARTING LABEL P/N 14085150. ALSO, REMOVE AND DISCARD FUSE LABELED "CRANK" FROM FUSE BLK #2 POSITION (3 AMP. FUSE). Footnotes 101 Thru 150 [101] Driveability correction for heavy chuggle. REQUIRES KIT P/N 25522748 CONTAINING: WIRING HARNESS JUMPER P/N 12043500, RELAY P/N 25522747, FOAM P/N 25522723, EGR P/N 17079799. [102] Cold startability adjustment. REQUIRES SUPPLEMENTARY TUNE-UP LABEL, SPARK BYPASS RELAY KIT P/N 14086983, SPARK PLUGS P/N 5614009, SUN VISOR STARTING LABEL P/N 14085150. ALSO, REMOVE AND DISCARD FUSE LABELED "CRANK" FROM FUSE BLK #2 POSITION (3 AMP. FUSE). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6043 [103] Cold startability adjustment. REQUIRES SUPPLEMENTARY TUNE-UP LABEL, SPARK BYPASS RELAY KIT P/N 14086983, SPARK PLUGS P/N 5614009, SUN VISOR STARTING LABEL P/N 14085150. ALSO, REMOVE AND DISCARD FUSE LABELED "CRANK" FROM FUSE BLK #2 POSITION (3 AMP. FUSE). [104] Cold startability adjustment. REQUIRES SUPPLEMENTARY TUNE-UP LABEL, SPARK BYPASS RELAY KIT P/N 14086983, SPARK PLUGS P/N 5614009, SUN VISOR STARTING LABEL P/N 14085150. ALSO, REMOVE AND DISCARD FUSE LABELED "CRANK" FROM FUSE BLK #2 POSITION (3 AMP. FUSE). [105] Surge. RETROFIT PROM - DOES NOT SUPERSEDE THE REGULAR REPLACEMENT SERVICE PROM. TO BE USED ONLY AS REQUIRED TO RESOLVE CASES OF CHUGGLE. [106] Surge and CODE 51. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE. [107] Surge and CODE 51. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE. [108] Surge and CODE 51. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE. [109] Surge and CODE 51. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE. [110] Surge. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE. [111] Surge and CODE 51. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE. [112] Surge and CODE 51. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE, DETONATION, OR FLATNESS. [113] Surge and CODE 51. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE, DETONATION, OR FLATNESS. [114] Surge, flatness or tip-in hesitation. RETROFIT PROM - DOES NOT SUPERSEDE THE REGULAR REPLACEMENT SERVICE PROMS. TO BE USED ONLY AS REQUIRED TO RESOLVE CASES OF CHUGGLE, DETONATION, OR FLATNESS. [115] FOR USE WITH P215/65 TIRES - USE 01228290 (SCAN I.D. = 8290). FOR USE WITH P235/60, P245/50 TIRES - USE 01228291 (SCAN I.D. = 8291). [116] FOR USE WITH P215/65 TIRES - USE 01228290 (SCAN I.D. = 8290). FOR USE WITH P235/60, P245/50 TIRES - USE 01228291 (SCAN I.D. = 8291). [117] Spark knock only. USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [118] Spark knock only. USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [119] Spark knock. USE 16143575 (SCAN I.D. = 3541) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143460 (SCAN I.D. = 3581) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [120] Detonation. USE 16143580 (SCAN I.D. = 3551) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143462 (SCAN I.D. = 3591) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [121] Stall, sags, hesitation. USE 16143575 (SCAN I.D. = 3541) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143460 (SCAN I.D. = 3581) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [122] USE 16143575 (SCAN I.D. = 3541) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143460 (SCAN I.D. = 3581) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [123] USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6044 USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [124] USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [125] USE 16143457 (SCAN I.D. = 3521) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143466 (SCAN I.D. = 3481) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [126] USE 16143452 (SCAN I.D. = 3491) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143463 (SCAN I.D. = 3451) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [127] USE 16143457 (SCAN I.D. = 3521) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143466 (SCAN I.D. = 3481) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [128] USE 16143452 (SCAN I.D. = 3491) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143463 (SCAN I.D. = 3451) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [129] Engine stall and/or hesitation after cold start. NEEDS AIR INJECTION SERVICE KIT (P/N 10115773) AND NEW VEHICLE EMISSION CONTROL LABEL. [130] Engine stall and/or hesitation after cold start. NEEDS AIR INJECTION SERVICE KIT (P/N 10115773) AND NEW VEHICLE EMISSION CONTROL LABEL. [131] Driveability conditions and/or stored engine codes. WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [132] Cold stall and chuggle. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PKG. WITH USED SCANNER ID 5644 BUT HAD A BCC OF AWJD. [133] Driveability conditions and/or stored engine codes. WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [134] Tip-in hesitation on acceleration; engine stall or sag on cold start; engine stall on deceleration; check engine light with CODES 23,25,33, or 34; or engine speed flare on clutch operation, with manual transmission equipped vehicle. WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [135] Tip-in hesitation on acceleration; engine stall or sag on cold start; engine stall on deceleration; check engine light with CODES 23,25,33, or 34; or engine speed flare on declutch operation with manual transmission equipped vehicle. WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [136] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [137] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [138] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [139] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [140] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [141] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [142] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6045 DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [143] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [144] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [145] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [146] PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [147] PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [148] PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [149] Tip-in hesitation on acceleration; engine stall or sag on cold start; engine stall on deceleration; check engine light with CODES 23,25,33, or 34; or engine speed flare on declutch operation with manual transmission equipped vehicle. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [150] Tip-in hesitation on acceleration; engine stall or sag on cold start; engine stall on deceleration; check engine light with CODES 23,25,33, or 34; or engine speed flare on declutch operation with manual transmission equipped vehicle. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). Footnotes 151 Thru 200 [151] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [152] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [153] Driveability improvement and eliminate FALSE "Service Engine Soon" lights. FOR 2WD USE 16120099 (SCAN I.D. = 9941). FOR 4WD USE 16120109 (SCAN I.D. = 9901). [154] Driveability improvement and eliminate FALSE "Service Engine Soon" lights. FOR 2.73 (GU2) AXLE USE 16120077 (SCAN I.D. = 9891). FOR 3.08 (GU4) AXLE USE 16120082 (SCAN I.D. = 9901). FOR 3.42 (GU6) AND 3.73 (GT4) AXLES USE 16120086 (SCAN I.D. = 9911). [155] Driveability improvement and eliminate FALSE "Service Engine Soon" lights. FOR 2WD USE 16120042 (SCAN I.D. = 9991). FOR 4WD USE 16120129 (SCAN I.D. = 0011). [156] Prom calibration. FOR FALSE CODE 44 ON LONG COAST DOWN, USE RETROFIT SERVICE PROM 01228486 AAND 1050. FOR REGULAR SERVICE REPLACEMENT, USE PROM 16062797 AAND 2798. [157] FOR FALSE CODE 44 ON LONG COAST DOWN, USE RETROFIT SERVICE PROM 01228487 AANF 1052. FOR REGULAR SERVICE REPLACEMENT, USE PROM 16062801 AANF 2802. [158] Spark knock only. USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [159] Spark knock only. USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6046 [160] Detonation. USE 16143580 (SCAN I.D. = 3551) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143462 (SCAN I.D. = 3591) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [161] USE 16143545 (SCAN I.D. = 3461) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093744). USE 16143465 (SCAN I.D. = 3471) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [162] USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [163] USE 16143545 (SCAN I.D. = 3461) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093744). USE 16143465 (SCAN I.D. = 3471) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [164] USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [165] USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [166] Hard start when hot and detonation. USE 16143457 (SCAN I.D. = 3521) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143466 (SCAN I.D. = 3481) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [167] Hard start when hot and detonation. USE 16143452 (SCAN I.D. = 3491) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143463 (SCAN I.D. = 3451) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [168] Engine stall and/or hesitation after cold start. NEEDS AIR INJECTION SERVICE KIT (P/N 10115773) AND NEW VEHICLE EMISSION CONTROL LABEL. [169] Cold stall and chuggle. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PKG. WHICH USED SCANNER ID 5644 BUT HAD A BCC OF AWJD. [170] Engine stall and/or hesitation after cold start. NEEDS AIR INJECTION SERVICE KIT (P/N 10115773) AND NEW VEHICLE EMISSION CONTROL LABEL. [171] Engine stall and/or hesitation after cold start. MUST BE ORDERED WITH SERVICE KIT P/N 10115773. [172] Driveability conditions and/or stored engine codes. WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [173] Driveability conditions and/or stored engine codes. WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [174] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [175] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [176] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [177] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [178] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [179] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6047 [180] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [181] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [182] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [183] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [184] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [185] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [186] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [187] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [188] Driveability conditions, and/or CODES 23,25,33,34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [189] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [190] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [191] Information on PROM calibrations. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [192] Information on PROM calibrations. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [193] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [194] Driveability conditions and/or stored engine codes. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [195] FOR USE WITH MODEL C1 TRUCKS - USE 16121162 (SCAN I.D. = 3511). FOR USE WITH MODEL C2, K, K2, AND K1000 TRUCKS USE 16121166 (SCAN I.D. = 3521). [196] Engine surge. ALSO REQUIRES INSTALLATION OF NEW EGR VALVE PACKAGE P/N 17112238 (CONTAINS EGR VALVE P/N 17090078 AND A GASKET). [197] Engine stall and/or hesitation after cold start. NEEDS AIR INJECTION SERVICE KIT (P/N 10115773) AND NEW VEHICLE EMISSION Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6048 CONTROL LABEL. [198] Engine stall and/or hesitation after cold start. NEEDS AIR INJECTION SERVICE KIT (P/N 10115773) AND NEW VEHICLE EMISSION CONTROL LABEL. [199] Cold stall and chuggle. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PKG. WHICH USED SCANNER ID 5644 BUT HAD A BCC OF AWJD. [200] Cold stall and chuggle. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PKG. WHICH USED SCANNER ID 5644 BUT HAD A BCC OF AWJD. Footnotes 201 Thru 250 [201] Cold engine extended crank. USE 16181863 (SCAN I.D. = 0844) FOR COLD START STALL. USE 16181859 (SCAN I.D. = 0834) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [202] Cold engine extended crank. USE 16181863 (SCAN I.D. = 0844) FOR COLD START STALL. USE 16181859 (SCAN I.D. = 0834) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [203] Cold engine extended crank. USE 16181863 (SCAN I.D. = 0844) FOR COLD START STALL. USE 16181859 (SCAN I.D. = 0834) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [204] Cold engine extended crank. USE 16181871 (SCAN I.D. = 0864) FOR COLD START STALL. USE 16181867 (SCAN I.D. = 0854) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [205] Cold engine extended crank. USE 16181871 (SCAN I.D. = 0864) FOR COLD START STALL. USE 16181867 (SCAN I.D. = 0854) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [206] Cold stall and chuggle. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PKG. WHICH USED SCANNER ID 5644 BUT HAD A BCC OF AWJD. [207] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [208] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [209] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [210] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [211] Engine stall, long cranks/idle/decel/surge. CANNOT BE USED ON VEHICLES THAT DO NOT HAVE DIGITAL EGR VALVES. [212] Cold stall and chuggle. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PKG. WHICH USED SCANNER ID 5644 BUT HAD A BCC OF AWJD. [213] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [214] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [215] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [216] Cold start extended crank. Engine starts with ignition key cycled. USE 16181883 (SCAN I.D. = 0894) FOR COLD START STALL. USE 16181875 (SCAN I.D. = 0874) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [217] Cold start extended crank, engine starts with ignition key cycled. USE 16181883 (SCAN I.D. = 0894) FOR COLD START STALL. USE 16181875 (SCAN I.D. = 0874) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6049 [218] Cold engine extended crank. USE 16181887 (SCAN I.D. = 0904) FOR COLD START STALL. USE 16181879 (SCAN I.D. = 0884) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [219] Cold engine extended crank. USE 16181887 (SCAN I.D. = 0904) FOR COLD START STALL. USE 16181879 (SCAN I.D. = 0884) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [220] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [221] Surge or chuggle on decel and/or rough idle. PROM CAN ONLY BE USED WITH ECM P/N 16144288. [222] Surge or chuggle on decel and/or rough idle. PROM CAN ONLY BE USED WITH ECM P/N 16144288. [223] Engine stall. MANUAL TRANSMISSION CARS SHOULD ALSO BE UPDATED WITH THE CLUTCH ANTICIPATE SWITCH PER DEALER SERVICE BULLETIN NO. 91-472-7C. [224] USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [225] USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [226] USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [227] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [228] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [229] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [230] Surge or chuggle on decel and/or rough idle. PROM CAN ONLY BE USED WITH ECM P/N 16144288. [231] MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [232] Driveability improvements. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [233] Driveability improvements. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [234] Driveablity improvements. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [235] Driveability improvements. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [236] Center Port Fuel Injection noise. FOR VEHICLES WITH SLEEVE BEARING ENGINES. [237] Neutral gear rattle only. COMBINATION DETONATION AND NEUTRAL GEAR RATTLE PROM AVAILABLE. [238] Driveability improvements. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [239] TCC chuggle. MODEL 2DDM TRANSMISSIONS - CHECK DEALER RECORDS TO SEE IF THE TORQUE CONVERTER HAS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6050 ALREADY BEEN REPLACED WITH P/N 8650935 (TAGGED BCC: DGAF). TRANS. WITH TORQUE CONVERTERS WITH P/N 8656959 (TAGGED BCC: DG5F) NEED TO REPLACE IT WITH P/N 8650935. [240] Unstable idle in park or neutral/poor driveability. FOR DEDICATED NATURAL GAS VEHICLES. ORDER WITH KIT P/N 12545589 UNLESS THE ONLY PROBLEM IS IDLE FLUCTUATION. [241] Driveability improvements. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [242] Information on PROM calibrations. CANNOT BE USED ON VEHICLES THAT DO NOT HAVE DIGITAL EGR VALVES. [243] TCC chuggle. MODEL 2DDM TRANSMISSIONS - CHECK DEALER RECORDS TO SEE IF THE TORQUE CONVERTER HAS ALREADY BEEN REPLACED WITH P/N 8650935 (TAGGED BCC: DGAF). TRANS. WITH TORQUE CONVERTERS WITH P/N 8656959 (TAGGED BCC: DG5F) NEED TO REPLACE IT WITH P/N 8650935. [244] TCC chuggle. MODEL 2DDM TRANSMISSIONS - CHECK DEALER RECORDS TO SEE IF THE TORQUE CONVERTER HAS ALREADY BEEN REPLACED WITH P/N 8650935 (TAGGED BCC: DGAF). TRANS. WITH TORQUE CONVERTERS WITH P/N 8656959 (TAGGED BCC: DG5F) NEED TO REPLACE IT WITH P/N 8650935. [245] Tip-in hesitation on acceleration; engine stall or sag on cold start; engine stall on deceleration; check engine light with CODES 23,25,33, or 34; or engine speed flare on declutch operation with manual transmission equipped vehicle. [246] Tip-in hesitation on acceleration; engine stall or sag on cold start; engine stall on deceleration; check engine light with CODES 23,25,33, or 34; or engine speed flare on declutch operation with manual transmission equipped vehicle. [247] Check engine light comes on while idling on vehicles equipped with Computer Controlled Emission System (C.C.E.S.), driven in altitudes above 3000 feet. [248] Engine may stop running during parking maneuver or during coast down at low speeds during ambient temperature above 85°F. [249] Tip-in hesitation on acceleration; engine stall or sag on cold start; engine stall on deceleration; check engine light with CODES 23,25,33, or 34; or engine speed flare on declutch operation with manual transmission equipped vehicle. [250] Surge on acceleration and/or at road load speeds, false "Service Engine Soon" light (CODE 32), poor driveability during warm up, Detonation under load. Footnotes 251 Thru 300 [251] Hesitation or sag during the first two minutes of cold operation while vehicle is under moderate to heavy throttle drive away, or TCC chuggle. [252] Cold start-stall, hesitation, or sag when the engine coolant is between 36°F to 111°F (2°C to 44°C); or Inadequate AC performance when driving at a steady speed and throttle position, between 24 to 64 MPH, when the cruise control is not being used. [253] Lack of throttle response on trucks equipped with governors; or hot restart driveaway sag, both governor and non-governor trucks. [254] Intermittent stall after cold start; engine stalling on coast down; hesitation cold; or ECM CODES E22,E26,E32,E55,E70, and/or E85 [255] PROM I.D. 7080 KJ is also acceptable for PROM I.D. 5853 KJ only. Requires Throttle body service P/N 17067144, EGR valve] service P/N 17067108 (FED), 17067144 (CAL), Injector service kit P/N 17067976. [256] Requires Throttle body service P/N 17067142, EGR valve service P/N 17067107 (FED), 17068210 (CAL), Injector service kit P/N 17067976. [257] FOR CHUGGLE AT 40-45 CONDITION, USE PROM ONLY. FOR TIP-IN HESITATION ONLY, USE EGR VALVE ONLY - P/N 17078431. FOR COLD DRIVEABILITY HESITATION, USE BOTH PROM AND EGR. [258] REQUIRES SUPPLEMENTARY TUNE-UP LABEL, SPARK BYPASS RELAY KIT P/N 015 14086983, SPARK PLUGS P/N 5614009, SUN VISOR STARTING LABEL P/N 015 14085150. ALSO, REMOVE AND DISCARD FUSE LABELED "CRANK" FROM FUSE BLK #2 POSITION (3 AMP. FUSE). [259] DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PACKAGE WITH USED SCANNER ID 5644 BUT HAD A [260] DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6051 BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PACKAGE WITH USED SCANNER ID 5644 BUT HAD A [261] DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PACKAGE WITH USED SCANNER ID 5644 BUT HAD A [262] MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY AT TEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [263] MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [264] MODEL 2DDM TRANS. CARS - CHECK DLR. RECORDS TO SEE IF THE TORQUE CONVERTER HAS ALREADY BEEN REPLACED WITH PN 8650935 (BCC: DGAF). TRANSMISSIONS WITH TORQUE CONVERTERS WITH PN 8656959 (BCC: DG5F) NEED TO HAVE THE TORQUE CONVERTER REPLACED W [265] MODEL 2DDM TRANS. CARS - CHECK DLR. RECORDS TO SEE IF THE TORQUE CONVERTER HAS ALREADY BEEN REPLACED WITH PN 8650935 (BCC: DGAF). TRANSMISSIONS WITH TORQUE CONVERTERS WITH PN 8656959 (BCC: DG5F) NEED TO HAVE THE TORQUE CONVERTER REPLACED W [266] Vehicles equipped with Computer Controlled Emission System (C.C.E.S) experience a Check Engine Light coming on while idling, usually when idling time exceeds 2 minutes with transmission in gear in altitudes above 3000 feet. [267] Cold driveability, use with PROM 5854 KJ (G057). PROM I.D. 7080 KJ IS ALSO ACCEPTABLE FOR PROM I.D. 5853 KJ ONLY. REQUIRES THROTTLE BODY SERVICE P/N 17067144, EGR VALVE SERVICE P/N 17067108 (FED), 17067144 (CAL), INJECTOR SERVICE KIT P/N 17067976. [268] Cold driveability, use with PROM 5853 KJ (G057). PROM I.D. 7079 KJ IS ALSO ACCEPTABLE FOR PROM I.D. 5854 KJ ONLY. REQUIRES THROTTLE BODY SERVICE P/N 17067144, EGR VALVE SERVICE P/N 17067108 (FED), 17067144 (CAL), INJECTOR SERVICE KIT P/N 17067976. [269] Cold driveability, use with PROM 5861 KK (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067107 (FED), 17068210 (CAL), INJECTOR SERVICE KIT P/N 17067976. [270] Cold driveability, use with PROM 5860 KK (G057). REQUIRES THROTTLE BODY SERVICE P/N 17067142, EGR VALVE SERVICE P/N 17067107 (FED), 17068210 (CAL), INJECTOR SERVICE KIT P/N 17067976. [271] Tip-in hesitation, lack low speed performance. Used with Manual transaxle vehicles with A/C only. Requires EGR TVS P/N 373510, and A.I.R. valve P/N 17082701. [272] Weak drive-away after cold start, requires EGR TVS P/N 373510. Also, for CALIFORNIA emissions, manual transaxle, replace A.I.R. management valve with PN 17082701. [273] Level road surge, tip-in hesitation, lack of low speed performance - for automatic transaxles only. (Requires EGR valve P/N 17068212). FOR FEDERAL - USE 01226055. FOR CALIFORNIA - USE 01226057. [274] Stall in coast down with clutch disengaged and A/C on, weak drive away after cold start , requires EGR TVS P/N 373510. Also, for CALIFORNIA emissions, manual transaxle, replace A.I.R. management valve with PN 17082701. [275] Idle shake, detonation (G043). FOR 2.5L EFI, AUTOMATIC TRANSAXLE, AND FIRST DESIGN (3-BOARD) ECM. THE SECOND DESIGN (2-BOARD) ECM HAS THE SPARK REVISION ALREADY INCORPORATED IN ITS PROM. [276] Chuggle/surge at 40-45 MPH, tip-in hesitation/sag, spark knock, requires EGR valve (G032). FOR CHUGGLE AT 40-45 CONDITION, USE PROM ONLY. FOR TIP-IN HESITATION ONLY, USE EGR VALVE ONLY - P/N 17078431. FOR COLD DRIVEABILITY HESITATION, USE BOTH PROM AND EGR. [277] Chuggle and surge at 35-55 MPH, requires EGR kit. REQUIRES KIT P/N 25522748 CONTAINING: WIRING HARNESS JUMPER P/N 12043500, RELAY P/N 25522747, FOAM P/N 25522723, EGR P/N 17079799. [278] CODE 42, spark knock, cold startability, plug fouling (G040). REQUIRES SUPPLEMENTARY TUNE-UP LABEL, SPARK BYPASS RELAY KIT P/N 14086983, SPARK PLUGS P/N 5614009, SUN VISOR STARTING LABEL P/N 14085150. ALSO, REMOVE AND DISCARD FUSE LABELED "CRANK" FROM FUSE BLK #2 POSITION (3 AMP. FUSE). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6052 [279] Chuggle and surge at 35-55 MPH, requires EGR kit (G040). REQUIRES KIT P/N 25522748 CONTAINING: WIRING HARNESS JUMPER P/N 12043500, RELAY P/N 25522747, FOAM P/N 25522723, EGR P/N 17079799. [280] Cold hesitation/sag, warm surge (G082). RETROFIT PROM SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OF DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE, DETONATION, OR FLATNESS. [281] TCC chuggle or surge (G043). WHEN INSTALLING PROM IN A CANADIAN 1985 NB, A CODE 13 WILL OCCUR AS THE VEHICLE WAS NOT EQUIPPED WITH AN O2 SENSOR. TO ELIMINATE THE CODE 13, NEED TO INSTALL O2 SENSOR # 8990741 AND CONNECT TO THE EXISTING PURPLE WIRE AND CONNECTOR IN THE [282] Surge or chuggle at 52-60 MPH (G071). RETROFIT PROM - DOES NOT SUPERSEDE THE REGULAR REPLACEMENT SERVICE PROM. TO BE USED ONLY AS REQUIRED TO RESOLVE CASES OF CHUGGLE. [283] Surge or chuggle at 52-60 MPH (G071). RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE. [284] Chuggle, hesitation, tip-in spark knock. RETROFIT PROM - SUPERSEDES ALL PREVIOUS SERVICE PROM PART NUMBERS. TO BE USED AS BOTH THE REGULAR SERVICE REPLACEMENT (PROM-DAMAGED OR DEFECTIVE), AND TO RESOLVE CASES OF CHUGGLE, DETONATION, OR FLATNESS. [285] Chuggle, hesitation, tip-in spark knock. RETROFIT PROM - DOES NOT SUPERSEDE THE REGULAR REPLACEMENT SERVICE PROMS. TO BE USED ONLY AS REQUIRED TO RESOLVE CASES OF CHUGGLE, DETONATION, OR FLATNESS. [286] FOR USE WITH P215/65 TIRES - USE 01228290 (SCAN I.D. = 8290). FOR USE WITH P235/60, P245/50 TIRES - USE 01228291 (SCAN I.D. = 8291). [287] FOR USE WITH P215/65 TIRES - USE 01228292 (SCAN I.D. = 8292). FOR USE WITH P235/60, P245/50 TIRES - USE 01228293 (SCAN I.D. = 8293). [288] FALSE CODES 33, 34, 43, rough idle, chuggle, hesitation (G006,G007). USED WITH VIN #119016 OR LATER ALUMINUM HEAD CORVETTES AND ALL CONVERTIBLE MODELS WITH AUTOMATIC TRANSMISSION, 2.59 (GM1) AXLE ONLY. [289] FALSE CODES 33, 34, 43, rough idle, chuggle, hesitation (G006,G007). USED FOR VIN #119016 OR LATER ALUMINUM HAED CORVETTES AND ALL CONVERTIBLE MODELS WITH AUTOMATIC TRANSMISSION, 2.73 (GU2)/3.07 (G44) AXLE ONLY. [290] Spark knock. USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [291] Spark knock. USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [292] Spark knock (G055). USE 16143575 (SCAN I.D. = 3541) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143460 (SCAN I.D. = 3581) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [293] Spark knock (G043). USE 16143580 (SCAN I.D. = 3551) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143462 (SCAN I.D. = 3591) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [294] Stalling, tip-in hesitation/sag, rough idle, cold driveability. USE 16143575 (SCAN I.D. = 3541) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143460 (SCAN I.D. = 3581) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [295] Hard hot restart (requires rubber bumper pkg PN 25004553, and a pulsator package PN 25094266), or CODE 42, intermittent high idle, spark knock (G055). [296] USE 16143575 (SCAN I.D. = 3541) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143460 (SCAN I.D. = 3581) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [297] USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [298] USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [299] USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6053 USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [300] Spark knock. USE 16143457 (SCAN I.D. = 3521) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143466 (SCAN I.D. = 3481) FOR CODE 42, SPARK KNOCK, HIGH IDLE. Footnotes 301 Thru 350 [301] Spark knock. USE 16143452 (SCAN I.D. = 3491) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143463 (SCAN I.D. = 3451) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [302] Hard start hot (requires installation of a rubber bumper pkg PN 25004553, and a pulsator pkg PN 25094266) or CODE 42, high idle, spark knock (G055). [303] USE 16143457 (SCAN I.D. = 3521) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143466 (SCAN I.D. = 3481) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [304] Hard hot restart (requires rubber bumper pkg PN 25004553, and a pulsator package PN 25094266), or CODE 42, intermittent high idle, spark knock (G055). [305] USE 16143452 (SCAN I.D. = 3491) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143463 (SCAN I.D. = 3451) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [306] Tip-in hesitation,stall,CODES 23,25,33,or 34, or speed flare on declutch op. w/man. trans. (CODE 23 or 25 require MAT sensor model year diagnostics) (G027). WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [307] CODES 23, 25, 33, 34, driveability and stalling (G027). PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [308] Tip-in hesitation,stall,CODES 23,25,33,or 34, or speed flare on declutch op. w/man. trans. (CODE 23 or 25 require MAT sensor model year diagnostics). PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [309] Code 23, 25, 33, 34, driveability and stalling. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [310] Tip-in hesitation,stall,CODES 23,25,33,or 34, or speed flare on declutch op. w/man. trans. (CODE 23 or 25 require MAT sensor model year diagnostics) (G027). PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [311] High emissions, exhaust odor, starting and driveability problems (G046). Requires Connector Bleed Assembly P/N 10105820 [312] FALSE CODES 43, 54, unstable idle. FOR 2.73 (GU2) AXLE USE 16120077 (SCAN I.D. = 9891). FOR 3.08 (GU4) AXLE USE 16120082 (SCAN I.D. = 9901). FOR 3.42 (GU6) AND 3.73 (GT4) AXLES USE 16120086 (SCAN I.D. = 9911). [313] Running change. FOR FALSE CODE 44 ON LONG COAST DOWN, USE RETROFIT SERVICE PROM 01228486 SCAN I.D. 8486, AAND 1050. FOR REGULAR SERVICE REPLACEMENT, USE PROM 16062797 SCAN I.D. 2223, AAND 2798. [314] Running change. FOR FALSE CODE 44 ON LONG COAST DOWN, USE RETROFIT SERVICE PROM 01228487 SCAN I.D. 8487, AANF 1052. FOR REGULAR SERVICE REPLACEMENT, USE PROM 16062801 SCAN I.D. 2233, AANF 2802. [315] Surge on acceleration and/or at road load speeds, false "Service Engine Soon" light (CODE 32), poor driveability during warm up, Detonation under load (G052). [316] Spark knock. USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [317] Spark knock. USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [318] Spark knock (G043). USE 16143580 (SCAN I.D. = 3551) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764). USE 16143462 (SCAN I.D. = 3591) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [319] Spark knock (G055). USE 16143545 (SCAN I.D. = 3461) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093744). USE 16143465 (SCAN I.D. = 3471) FOR CODE 42, SPARK KNOCK, HIGH IDLE. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6054 [320] CODE 42, spark knock, intermittent high idle. IF MAJOR CONDITION IS HARD HOT ENGINE RESTART, PROM ALSO REQUIRES INSTALLATION OF A RUBBER BUMPER PKG PN 25004553, AND PULSATOR PKG PN 25094266. [321] USE 16143545 (SCAN I.D. = 3461) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093744). USE 16143465 (SCAN I.D. = 3471) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [322] USE 16143570 (SCAN I.D. = 3531) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143459 (SCAN I.D. = 3571) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [323] USE 16143455 (SCAN I.D. = 3511) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115764, FUEL SENDER P/N 25093526). USE 16143453 (SCAN I.D. = 3501) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [324] Spark knock. USE 16143457 (SCAN I.D. = 3521) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143466 (SCAN I.D. = 3481) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [325] Spark knock. USE 16143452 (SCAN I.D. = 3491) FOR HOT HARD RESTART (REQUIRES FUEL PUMP P/N 25115925, FUEL SENDER P/N 25092778). USE 16143463 (SCAN I.D. = 3451) FOR CODE 42, SPARK KNOCK, HIGH IDLE. [326] Tip-in hesitation, stall, CODES 23, 25, 33, or 34, or speed flare on declutch op. w/man. trans. (CODE 23 or 25 require MAT sensor model year diagnostics) (G027). WITH THIS PROM INSTALLED, USE 1987-88 2.8L SPEED DENSITY ENGINE DRIVEABILITY AND EMISSIONS MANUAL. [327] CODES 23, 25, 33, 34. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [328] Tip-in hesitation,stall,CODES 23,25,33,or 34, or speed flare on declutch op. w/ man. trans. (CODE 23 or 25 require MAT sensor model year diagnostics). PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [329] Tip-in hesitation,stall,CODES 23,25,33,or 34, or speed flare on declutch op. w/ man. trans. (CODE 23 or 25 require MAT sensor model year diagnostics) (G027). PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [330] CODES 23, 25, 33, 34, driveability and stalling (G027). PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [331] Code 23, 25, 33, 34, driveability and stalling. PROM UPDATE ELIMINATES MAF SENSOR, REPLACING IT WITH A SPEED DENSITY SYSTEM. WITH A 1990 OR EARLIER PRIMARY CARTRIDGE, I.D. VEHICLE ON SCANNER AS A 1989 MODEL (VIN = K-1-W). [332] FOR USE WITH MODEL C1 TRUCKS - USE 16121162 (SCAN I.D. = 3511). FOR USE WITH MODEL C2, K, K2, AND K1000 TRUCKS USE 16121166 (SCAN I.D. = 3521). [333] Surge on acceleration and/or at road load speeds, false "Service Engine Soon" light (CODE 32), poor driveability during warm up, Detonation under load (G052). [334] Cold engine extended crank. USE 16181863 (SCAN I.D. = 0844) FOR COLD START STALL. USE 16181859 (SCAN I.D. = 0834) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [335] [Cold engine extended crank. USE 16181871 (SCAN I.D. = 0864) FOR COLD START STALL. USE 16181867 (SCAN I.D. = 0854) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [336] Engine does not stay running on initial cold start and chuggle at 35-45 MPH with TCC engaged. New MEM-CAL may affect fuel economy. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PACKAGE WITH SCANNER ID 5644 BUT A BCC OF A] [337] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [338] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [339] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6055 [340] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [341] Hesitation or sag during the first two minutes of cold operation while vehicle is under moderate to heavy throttle driveaway, or TCC chuggle. [342] Cold start-stall, hesitation, or sag when the engine coolant is between 36°F - 111°F (2°C 44°C); or Inadequate A/C performance when driving at steady speed and throttle position, between 24 - 64 MPH, when the cruise control is not being used. [343] Engine does not stay running on initial cold start and chuggle at 35-45 MPH with TCC engaged. New MEM-CAL may affect fuel economy. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PACKAGE WITH SCANNER ID 5644 BUT A BCC OF A [344] Cold engine extended crank. USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [345] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [346] Cold engine extended crank. USE 16181883 (SCAN I.D. = 0894) FOR COLD START STALL. USE 16181875 (SCAN I.D. = 0874) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [347] Cold engine extended crank. USE 16181887 (SCAN I.D. = 0904) FOR COLD START STALL. USE 16181879 (SCAN I.D. = 0884) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [348] Service Engine Soon light (SES) with a code 43 or tip-in sag, tip-in hesitation, surge at WOT, or spark detonation when cold. [349] Engine stall. MANUAL TRANSMISSION CARS SHOULD ALSO BE UPDATED WITH THE CLUTCH ANTICIPATE SWITCH PER DEALER SERVICE BULLETIN NO. 91-472-7C. [350] Engine does not stay running on initial cold start and chuggle at 35-45 MPH with TCC engaged. New MEM-CAL may affect fuel economy. DO NOT RELY ON THE SCANNER ID TO DETERMINE WHICH PROM IS IN A VEHICLE. LOOK AT THE BCC ON THE PROM TO BE SURE. DO NOT CONFUSE WITH SOME 1991 MODELS WITH A 2.84 AXLE RATIO AND A FEDERAL EMISSIONS PACKAGE WITH SCANNER ID 5644 BUT A BCC OF A. Footnotes 351 Thru 400 [351] USE 16165848 (SCAN I.D. = 5614) FOR COLD START STALL. USE 16165843 (SCAN I.D. = 5624) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [352] USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [353] Cold engine extended crank. USE 16165839 (SCAN I.D. = 5634) FOR COLD START STALL. USE 16165829 (SCAN I.D. = 5644) ONLY IF REQUIRED TO SOLVE BOTH COLD START STALL AND CHUGGLE. [354] Lack of throttle response on trucks equipped with governors; or hot restart driveaway sag, both governor and non-governor trucks. [355] Low speed driveability or detonation. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [356] Tip-in hesitation, sag, backfire, spark knock. MAKE CERTAIN THE VEHICLE HAS BEEN UPDATED WITH PREVIOUSLY ATTEMPTED SERVICE FIXES AS FOLLOWS: EGR VALVE P/N 17090156 (STAMPED ON VALVE) 17112373 (GMSPO KIT), PCV VALVE P/N 25098542, ESC MODULE P/N 16175099 (BCC=BARC). [357] Hesitation or sag during the first two minutes of cold operation while vehicle is under moderate to heavy throttle driveaway, or TCC chuggle. [358] Sustained detonation/knock. AUTOMATIC TRANSMISSIONS REQUIRE TORQUE CONVERTER CLUTCH (TCC) CALIBRATION. USE OF THIS PROM IN A NON-DETONATING ENGINE MAY RESULT IN DEGRADED DRIVEABILITY. [359] High emissions, exhaust odor, starting and driveability problems (G046). Requires Connector Bleed Assembly P/N 10105820 [360] Neutral gear rattle. MAY ALSO REQUIRE CLUTCH DRIVEN PLATE P/N 15961141, AND CLUTCH PILOT BEARING P/N 14061685. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Application and ID > Introducing the GM PROM Cross Reference Index > Page 6056 COMBINATION DETONATION AND NEUTRAL GEAR RATTLE PROM AVAILABLE. [361] Malfunction Indicator Lamp (check engine light) illuminates and may set a DTC 24 (VSS Circuit Fault) during a California State Emissions Test. [362] Higher than normal hydrocarbon emissions during the idle portion of the inspection and maintenance test. Also, may exhibit a slight detonation during a light throttle acceleration [363] TCC chuggle. MODEL 2DDM TRANS. - CHECK DEALER RECORDS TO SEE IF THE TORQUE CONVERTER HAS BEEN REPLACED WITH P/N 8650935 (BCC: DGAF). TRANS. WITH TORQUE CONVERTERS WITH P/N 8656959 (BCC: DG5F) NEED TO HAVE THE TORQUE CONVERTER REPLACED WITH P/N 8650935. [364] Cold start stall, cold tip in hesitation and/or a cold rough idle after extended idling. Additionally, in 40-50°F ambient temp., fogging on the inside of the front windshield which does not clear with the defroster on occurs. [365] Poor throttle response, stall, misfire, poor cold or hot start, extended crank of the starter with a hot engine, and/or vehicle will start and then stall when the engine is hot. MT vehicles may also experience decel. stall and poor accel. performance. [366] Poor throttle response, stalling, misfire, poor cold or hot starting, extended cranking of the starter with a hot engine, and/or vehicle will start and then stall when the engine is hot. USED WITH MANUAL TRANSMISSION ONLY. [367] MIL illuminates and/or store a DTC 32 (EGR error) with no noticeable driveability concern, usually occurring while climbing a grade. [368] MIL illuminates and/or store a DTC 32 (EGR error) with no noticeable driveability concern, usually occurring while climbing a grade, towing a trailer or driving into a strong head wind. [369] High emissions, exhaust odor, starting and driveability problems (G046). Requires Connector Bleed Assembly P/N 10105820 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Description and Operation > CALPAK PROM - Programmable Read Only Memory: Description and Operation CALPAK CAUTION: If the computer is found to be defective and needs replacement, remove the old CALPAK and PROM, then place both into the replacement computer. When replacing the COMPUTER always transfer the BROADCAST CODE and PRODUCTION ECM/PCM NUMBER to the service label on the replacement computer. DESCRIPTION: The resistor network calibration called a CALPAK is located inside the computer. Its appearance and service is similar to the PROM. The CALPAK allows fuel to be delivered if other parts of the computer fail. The CALPAK provides the computer with calibrations for: ^ Cold Start Cranking. ^ Limp home fuel (fuel backup mode). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Description and Operation > CALPAK > Page 6059 PROM - Programmable Read Only Memory: Description and Operation EEPROM CAUTION: The EEPROM is soldered to the COMPUTER and cannot be serviced separately. Reprogramming of EEPROM information is necessary when replacing a COMPUTER, or when changing the engine and/or transaxle calibrations. Failure to do this will cause the vehicle to have a no start or poor running condition. It is essential that a replacement COMPUTER be reprogrammed with the correct VIN, option content, tire size, and calibration information. Reprogramming of the EEPROM is only possible with the Service Stall System (SSS) hardware available at authorized dealer locations. Check with a dealer before performing COMPUTER replacement or EEPROM reprogramming. DESCRIPTION: The term EEPROM is defined as Electronically Erasable Programmable Read Only Memory (EEPROM) in the COMPUTER. The EEPROM stores vehicle information such as engine and transaxle calibrations, vehicle identification number, programmable vehicle option content and MALF history. Vehicle information stored on the EEPROM has a major effect on how the vehicle will operate. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Description and Operation > CALPAK > Page 6060 PROM - Programmable Read Only Memory: Description and Operation EPROM CAUTION: The EPROM is serviceable in some applications and can be removed for replacement. If the COMPUTER is found to be defective and needs replacement, remove the old EPROM if applicable and place into the new computer. When replacing the COMPUTER always transfer the BROADCAST CODE and PRODUCTION ECM/PCM NUMBER to the service label on the replacement computer. DESCRIPTION: The term EPROM means Erasable Programmable Read Only Memory (EPROM). The EPROM functions in the same manner as a regular PROM and is programmed with data pertaining to the vehicles weight, engine, transmission, axle ratio etc. Automotive technicians do not ERASE or PROGRAM the EPROM in the field. Instead, the EPROM is serviced in one of two manners. Some applications are soldered to the circuit board and require both the computer and EPROM to be replaced as a complete unit. Other applications allow for the EPROM only to replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Description and Operation > CALPAK > Page 6061 PROM - Programmable Read Only Memory: Description and Operation MEMCAL CAUTION: If the COMPUTER is found to be defective and needs replacement, remove the old MEMCAL and place it into the replacement computer. When replacing the COMPUTER always transfer the BROADCAST CODE and PRODUCTION ECM/PCM NUMBER to the service label on the replacement computer. DESCRIPTION: The MEMCAL assembly contains both the functions of the PROM and the CALPAK. Like the PROM, it contains the calibrations needed for a specific vehicle. It also is the fuel back up control for the computer should it become damaged or faulty. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Description and Operation > CALPAK > Page 6062 PROM - Programmable Read Only Memory: Description and Operation PROM CAUTION: If the computer is found to be defective and needs replacement, remove the old PROM and place it into the replacement computer. Some ECM's are equipped with another chip called a CALPAK. If the computer is equipped with a CALPAK chip, it will be located next to the PROM and must be transferred along with the PROM. When replacing the computer always transfer the BROADCAST CODE and PRODUCTION ECM/PCM NUMBER to the service label on the replacement computer. DESCRIPTION: To allow one type of computer to be used for many different vehicles, a device called a Programable Read Only Memory (PROM) unit is used. The PROM is located inside the computer and has system calibration information based upon the vehicle's axle ratio, engine, transmission, weight, and other specific configurations of the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Description and Operation > Page 6063 PROM - Programmable Read Only Memory: Testing and Inspection Some control modules may have problems due to cracked solder joints on the circuit board. These internal control module problems can cause the following symptoms: ^ Failure to start or vehicle is stalling. ^ The "CHECK ENGINE" "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR" light will flash or light up, but no trouble codes will be present. ^ Vehicle instrument panel displays may be inoperative. ^ The control module may or may not communicate with the scanner. ^ Other intermittent driveability problems. Incorrect PROM or MEMCAL removal and replacement can create solder joint problems or aggravate an existing condition. See PROM or MEMCAL INSTALLATION for proper procedures. If a solder joint problem results in a "hard" failure, normal test procedures will usually pinpoint a faulty control module. Many symptoms caused by poor solder joints in the control module result in intermittent problems, but they may be hard to duplicate during troubleshooting. Control modules with solder joint problems are sensitive to heat and vibration. You can check for these internal control module problems in either, or both, of the following ways: ^ Remove the control module from its mounting bracket and extend it on the harness so that you can expose it to the vehicle heater ducts. Alternatively, use the flexible duct to route air from the heater to the control module location. Then run the engine and operate the heater at the "MAX HEAT" position. This exposes the control module to approximately 140°F. ^ With the engine running, tap on the control module several times with your hand or finger tips to simulate vehicle vibration. If the engine stumbles or stalls, the "CHECK ENGINE" "SERVICE ENGINE SOON" or "MALFUNCTION INDICATOR" light flashes, or any of the previous symptoms occur, the control module may have bad solder joints on the circuit board. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Service and Repair > CALPAK PROM - Programmable Read Only Memory: Service and Repair CALPAK 1. Remove ECM from vehicle. 2. Remove ECM access cover. 3. Remove Calibration Pack (CALPAK) using removal tool shown. Grasp the CALPAK carrier on the narrow ends only. Gently rock the carrier from end to end while applying a firm upward force. 4. Inspect the reference end of the CALPAK carrier and carefully set aside. Do not remove the CALPAK from the carrier to confirm CALPAK correctness. The notch in the CALPAK is referenced to the small notch in the carrier. The small notch of the carrier must be aligned with the small notch in the socket. CAUTION: ANY TIME THE CALPAK IS INSTALLED BACKWARDS AND THE IGNITION SWITCH IS TURNED ON, THE CALPAK IS DESTROYED. 5. Install the CALPACK by pressing on the CALPAK carrier until it is firmly seated in the socket. Do not press on the CALPAK, only the carrier. 6. Install ECM access cover. 7. Install ECM and perform a DIAGNOSTIC CIRCUIT CHECK to confirm proper installation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Service and Repair > CALPAK > Page 6066 PROM - Programmable Read Only Memory: Service and Repair EEPROM CAUTION: The Erasable Programmable Read Only Memory (EEPROM) is a permanent memory that is physically soldered to the circuit boards within the computer. It is not serviceable and should not be removed for replacement. If COMPUTER replacement is performed, reprogramming of the EEPROM will be necessary. Failure to do this will cause the vehicle to have a no start or poor running condition. Reprogramming of the EEPROM is only possible with the Service Stall System (SSS) hardware available at authorized dealer locations. Check with a dealer before performing COMPUTER replacement or EEPROM reprogramming. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Service and Repair > CALPAK > Page 6067 PROM - Programmable Read Only Memory: Service and Repair EPROM REMOVAL: ^ DO NOT remove an EPROM from its packing material until you are ready to install it. DO NOT hold an EPROM by its pins. ^ Before entering a vehicle to remove or replace an EPROM, touch an exposed metal part of the vehicle to discharge any static charge from your body or use anti-static wrist straps. Avoid sliding across upholstery or carpeting when removing or installing an EPROM. If this is not possible, touch an exposed metal part of the vehicle with your free hand before removing or replacing an EPROM. ^ When available, use an antistatic grounding strap attached to your wrist and clipped to a metal part of the vehicle body to prevent static charges from accumulating. Antistatic conductive floormats are also available. ^ It may be desirable to remove the computer for EPROM replacement. ^ Remove computer access cover. ^ Unlock the locking levers by pressing outward toward the sides of the EPROM. ^ Remove EPROM from its socket INSTALLATION: EPROM/MEM-CAL Unit Installation ^ Install the replacement EPROM in the same direction. ^ VERY GENTLY PRESS down on the ends of the EPROM until the locking levers are rotated toward the sides of the EPROM. ^ NOTE: To avoid Computer damage, do not press on the ends of the EPROM until the levers snap into place. Do not use any vertical force beyond the minimum required to engage the EPROM into its socket. ^ While continuing light pressure on the ends of the EPROM, use your index fingers to press the locking levers inward until they are snapped into place. Listen for the click. ^ Install the access cover on the computer. ^ Perform FUNCTIONAL CHECK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Service and Repair > CALPAK > Page 6068 PROM - Programmable Read Only Memory: Service and Repair MEMCAL CONDITION: When installing a service replacement computer, the use of incorrect MEMCAL installation procedures may cause the computer to fail before it can be installed in the vehicle. This condition may appear as if the computer were defective when shipped to the dealership, when in fact it was damaged while being installed. In addition this condition may also occur when installing an updated MEMCAL into the vehicles original equipment computer. CAUSE: Excessive vertical force may be applied to the MEMCAL resulting in flexing of the circuit board and damage to the connections between the circuit board and attached components. Excessive vertical force may be generated in two ways. ^ Incorrect MEMCAL installation procedures. ^ Interference between MEMCAL and cover. IMPORTANT CORRECTION: This procedure supersedes any instructions regarding MEMCAL installation dated prior to September 1990. 1. Inspect the MEMCAL to determine if a cork spacer is glued to the top side of the MEMCAL assembly. If so, remove it prior to installation. 2. Align small notches with matching notches in Computer MEMCAL socket. 3. VERY GENTLY PRESS down on the ends of the MEMCAL until the locking levers are rotated toward the sides of the MEMCAL. NOTE: To avoid computer damage, do not press on the ends of the MEMCAL until the levers snap into place. Do not use any vertical force beyond the minimum required to engage the MEMCAL into its socket. 4. While continuing light pressure on the ends of the MEMCAL, use your index fingers to press the locking levers inward until they are snapped into place. Listen for the click. 5. Install MEMCAL cover and install computer cover. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Powertrain Management > PROM - Programmable Read Only Memory > Component Information > Service and Repair > CALPAK > Page 6069 PROM - Programmable Read Only Memory: Service and Repair PROM 1. Remove ECM from vehicle. 2. Remove ECM access cover. PROM Removal 3. Remove PROM using the rocker-type PROM removal tool shown. Engage one end of the PROM carrier with the hook end of the tool. Press on the vertical bar end of the tool and rock the engaged end of the PROM carrier up as far as possible. Engage the opposite end of the PROM carrier in the same manner and rock this end up as far as possible. Repeat this process until the PROM carrier and PROM are free of the PROM socket. The PROM carrier with the PROM in it should lift off of the PROM socket easily. 4. Inspect the reference end of the PROM carrier and carefully set aside. Do not remove the PROM from the carrier to confirm PROM correctness. The notch in the PROM is referenced to the small notch in the carrier. The small notch of the carrier must be aligned with the small notch in the socket. CAUTION: ANY TIME THE PROM IS INSTALLED BACKWARDS AND THE IGNITION SWITCH IS TURNED ON, THE PROM IS DESTROYED. 5. Install PROM by pressing on the PROM carrier until it is firmly seated in the socket. Do not press on the PROM, only the carrier. 6. Install ECM access cover. 7. Install ECM and perform a DIAGNOSTIC CIRCUIT CHECK to confirm proper installation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Actuators and Solenoids - Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Torque Converter Clutch Solenoid: Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Actuators and Solenoids - Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6077 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Actuators and Solenoids - Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6078 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Actuators and Solenoids - Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > Page 6079 Torque Converter Clutch Solenoid: Service and Repair REPLACE 1. Raise and support vehicle. 2. Disconnect heated oxygen sensor. 3. Remove catalytic converter to muffler attaching bolts and nuts. 4. Remove catalytic converter hanger to catalytic converter bolts. 5. Remove righthand side dampener assembly. 6. Remove nuts holding exhaust pipe to exhaust manifold. 7. Remove converter and pipe assembly from vehicle. 8. Remove oil pan and oil filter assembly. 9. Disconnect external wiring harness from transmission pass through connector. 10. Remove accumulator cover attaching bolts. 11. Remove 1-2 accumulator cover, piston and spring. 12. Disconnect electrical connectors. 13. Remove pressure control solenoid retainer bolt, then the retainer and solenoid. 14. Remove TCC solenoid retaining bolts. 15. Remove pass-through electrical connector from transmission case by positioning the small end of power piston seal protector and diaphragm retainer installer tool No. J-28458 or equivalent, over the top of the connector, then twist tool to release the four tabs while at the same time pulling the harness through the case. 16. Remove TCC solenoid with wiring harness from transmission case. 17. Reverse procedure to install, noting the following: a. Tighten TCC solenoid retaining bolt to specification. b. Tighten pressure control solenoid retaining bolt to specification. c. When installing 1-2 accumulator piston to accumulator cover, the piston legs must face towards the case. d. Tighten accumulator attaching bolts to specification Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Torque Converter Clutch Solenoid: Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6086 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6087 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > Page 6088 Torque Converter Clutch Solenoid: Service and Repair REPLACE 1. Raise and support vehicle. 2. Disconnect heated oxygen sensor. 3. Remove catalytic converter to muffler attaching bolts and nuts. 4. Remove catalytic converter hanger to catalytic converter bolts. 5. Remove righthand side dampener assembly. 6. Remove nuts holding exhaust pipe to exhaust manifold. 7. Remove converter and pipe assembly from vehicle. 8. Remove oil pan and oil filter assembly. 9. Disconnect external wiring harness from transmission pass through connector. 10. Remove accumulator cover attaching bolts. 11. Remove 1-2 accumulator cover, piston and spring. 12. Disconnect electrical connectors. 13. Remove pressure control solenoid retainer bolt, then the retainer and solenoid. 14. Remove TCC solenoid retaining bolts. 15. Remove pass-through electrical connector from transmission case by positioning the small end of power piston seal protector and diaphragm retainer installer tool No. J-28458 or equivalent, over the top of the connector, then twist tool to release the four tabs while at the same time pulling the harness through the case. 16. Remove TCC solenoid with wiring harness from transmission case. 17. Reverse procedure to install, noting the following: a. Tighten TCC solenoid retaining bolt to specification. b. Tighten pressure control solenoid retaining bolt to specification. c. When installing 1-2 accumulator piston to accumulator cover, the piston legs must face towards the case. d. Tighten accumulator attaching bolts to specification Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Band, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Band: Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Band, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6093 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Band, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6094 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Case, A/T > Component Information > Technical Service Bulletins > A/T - Cracked Case Diagnosis Case: Technical Service Bulletins A/T - Cracked Case Diagnosis Bulletin No.: 02-07-30-024B Date: August 18, 2005 INFORMATION Subject: Diagnosis of Cracked or Broken Transmission Case Models: 2006 and Prior Cars and Light Duty Trucks 2006 and Prior HUMMER H2 2006 HUMMER H3 2005-2006 Saab 9-7X with 4L60/4L60-E/4L65-E or 4L80-E/4L85-E or Allison(R) Series 1000 Automatic Transmission Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 02-07-30-024A (Section 07 - Transmission/Transaxle). Diagnosing the cause of a cracked or broken transmission case requires additional diagnosis and repair or a repeat failure will occur. A cracked or broken transmission case is most often the result of abnormal external torsional forces acting on the transmission case. If none of the conditions listed below are apparent, an internal transmission component inspection may be required. Repairs of this type may be the result of external damage or abuse for which General Motors is not responsible. They are not the result of defects in materials or workmanship. If in doubt, contact your General Motors Service Representative. The following items should be considered: ^ It is important to inspect the vehicle for signs of an out of line condition, impact damage or foreign material to the following components: - The transmission - The engine mounts - The transmission rear mount and crossmember - Vehicle frame damage that alters the front to rear alignment of the driveshaft - The driveshafts (both front and rear) - The wheels (caked with mud, concrete, etc.) - The tires (roundness, lack of cupping, excessive balance weights) - The transfer case (if the vehicle is 4WD) ^ A worn or damaged driveshaft U-Joint has shown to be a frequent cause of transmission case cracking, especially on vehicles that see extended periods of highway driving. Always inspect the U-joint condition when diagnosing this condition. ^ For driveshaft damage or imbalance, Inspect the driveshafts (both front and rear) for dents, straightness/runout or signs of missing balance weights. Also, inspect for foreign material such as undercoat sprayed on the driveshaft. ^ The driveshaft working angles may be excessive or non-canceling, especially if the vehicle carrying height has been altered (lifted or lowered) or if the frame has been extended or modified. ^ Damaged or worn upper or lower rear control arms or bushings. ^ A rear axle that is not seated in the rear spring properly (leaf spring vehicles). ^ Broken rear springs and or worn leaf spring bushings. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Case, A/T > Component Information > Technical Service Bulletins > A/T - Cracked Case Diagnosis > Page 6099 In some cases, the customer may not comment about a vibration but it is important to test drive the vehicle while using the electronic vibration analysis tool in an attempt to locate the cause of the torsional vibration. Refer to the Vibration Diagnosis and Correction sub-section of the appropriate Service Manual for more details on diagnosing and correcting vibrations. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Channel Plate, A/T > Component Information > Technical Service Bulletins > A/T Control - DTC P0756 Diagnostic Tips Channel Plate: Technical Service Bulletins A/T Control - DTC P0756 Diagnostic Tips INFORMATION Bulletin No.: 01-07-30-036H Date: January 29, 2009 Subject: Diagnostic Tips for Automatic Transmission DTC P0756, Second, Third, Fourth Gear Start Models: 2009 and Prior GM Passenger Cars and Light Duty Trucks 2009 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X with 4L60-E, 4L65-E or 4L70E Automatic Transmission (RPOs M30, M32 or M70) Supercede: This bulletin is being revised to add the 2009 model year and add details regarding spacer plates. Please discard Corporate Bulletin Number 01-07-30-036G (Section 07 - Transmission/Transaxle). Some dealership technicians may have difficulty diagnosing DTC P0756, 2-3 Shift Valve Performance on 4L60-E, 4L65-E or 4L70E automatic transmissions. As detailed in the Service Manual, when the PCM detects a 4-3-3-4 shift pattern, DTC P0756 will set. Some customers may also describe a condition of a second, third or fourth gear start that may have the same causes but has not set this DTC yet. Below are some tips when diagnosing this DTC: ^ This is a performance code. This means that a mechanical malfunction exists. ^ This code is not set by electrical issues such as a damaged wiring harness or poor electrical connections. Electrical problems would cause a DTC P0758, P0787 or P0788 to set. ^ The most likely cause is chips/debris plugging the filtered AFL oil at orifice # 29 on the top of the spacer plate (48). This is a very small hole and is easily plugged by a small amount of debris. It is important to remove the spacer plate and inspect orifice # 29 and the immediate area for the presence of chips/debris. Also, the transmission case passage directly above this orifice and the valve body passage directly below should be inspected and cleaned of any chips/debris. For 2003 and newer vehicles the spacer plate should be replaced. The service replacement spacer plate is a bonded style with gaskets and solenoid filter screens bonded to the spacer plate. These screens can help to prevent plugging of orifice # 29 caused by small debris or chips. ^ This code could be set if the 2-3 shift valve (368) were stuck or hung-up in its bore. Inspect the 2-3 shift valve (368) and the 2-3 shuttle valve (369) for free movement or damage and clean the valves, the bore and the valve body passages. ^ This code could be set by a 2-3 shift solenoid (367b) if it were cracked, broken or leaking. Refer to Shift Solenoid Leak Test in the appropriate Service Manual for the leak test procedure. Based on parts return findings, a damaged or leaking shift solenoid is the least likely cause of this condition. Simply replacing a shift solenoid will not correct this condition unless the solenoid has been found to be cracked, broken or leaking. It is important to also refer to the appropriate Service Manual or Service Information (SI) for further possible causes of this condition. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > Customer Interest: > 08-07-30-027 > Jun > 08 > A/T - No Movement in Drive or 3rd Gear Clutch: Customer Interest A/T - No Movement in Drive or 3rd Gear TECHNICAL Bulletin No.: 08-07-30-027 Date: June 04, 2008 Subject: No Movement When Transmission is Shifted to Drive or Third - Normal Operation When Shifted to Second, First or Reverse (Replace Forward Sprag Assembly) Models: 1982 - 2005 GM Passenger Cars and Light Duty Trucks 2006 - 2007 Buick Rainier 2006 Cadillac Escalade, Escalade ESV, Escalade EXT 2006 Chevrolet SSR 2006 - 2008 Chevrolet Avalanche, Colorado, Express, Silverado Classic, Silverado, Suburban, Tahoe, TrailBlazer 2006 GMC Yukon Denali, Yukon Denali XL 2006 - 2008 GMC Canyon, Envoy, Savana, Sierra Classic, Sierra, Yukon, Yukon XL 2006 Pontiac GTO 2006 - 2007 HUMMER H2 2006 - 2008 HUMMER H3 2006 - 2008 Saab 9-7X with 4L60, 4L60E, 4L65E or 4L70E Automatic Transmission (RPOs MD8, M30, M32, M33 or M70) Condition Some customers may comment that the vehicle has no movement when the transmission is shifted to DRIVE or THIRD position, but there is normal operation when it is shifted to SECOND, FIRST or REVERSE position. Cause This condition may be caused by a damaged forward sprag assembly (642). Correction When inspecting the sprag, it is important to test the sprag for proper operation by holding the outer race (644) with one hand while rotating the input sun gear (640) with the other hand. The sun gear should rotate only in the counterclockwise direction with the input sun gear facing upward. If the sprag rotates in both directions or will not rotate in either direction, the sprag elements should be inspected by removing one of the sprag assembly retaining rings (643). Refer to SI Unit Repair section for forward clutch sprag disassembly procedures. If the sprag is found to be damaged, make repairs to the transmission as necessary. A new forward roller clutch sprag assembly is now available from GMSPO. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > Customer Interest: > 08-07-30-027 > Jun > 08 > A/T - No Movement in Drive or 3rd Gear > Page 6112 If clutch debris is found, it is also very important to inspect the Pressure Control (PC) solenoid valve (377) fluid screens. Clean or replace the PC solenoid (377) as necessary. It is also important to flush and flow check the transmission oil cooler using J45096. Refer to SI Automatic Transmission Oil Cooler Flushing and Flow Test for the procedure. The notches above each sprag must point up as shown when assembled into the outer race. Bearing Assembly, Input Sun Gear Snap Ring, Overrun Clutch Hub Retaining Hub, Overrun Clutch Wear Plate, Sprag Assembly Retainer and Race Assembly, Sprag Forward Sprag Assembly Retainer Rings, Sprag Assembly Outer Race, Forward Clutch Washer, Thrust (Input Carrier to Race) The following information applies when this sprag is used in 1982-86 transmissions. The new design sprag can be used on models 1982 through 1986, by replacing the entire assembly (637 - 644). Individual components are NOT Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > Customer Interest: > 08-07-30-027 > Jun > 08 > A/T - No Movement in Drive or 3rd Gear > Page 6113 interchangeable. Important: The wear plate (640) and input thrust washer (660) are not required with the new sprag. Use of the thrust washer and wear plate with the new sprag assembly will cause a misbuild (correct end play cannot be obtained). Parts Information Warranty Information For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Clutch: > 08-07-30-027 > Jun > 08 > A/T - No Movement in Drive or 3rd Gear Clutch: All Technical Service Bulletins A/T - No Movement in Drive or 3rd Gear TECHNICAL Bulletin No.: 08-07-30-027 Date: June 04, 2008 Subject: No Movement When Transmission is Shifted to Drive or Third - Normal Operation When Shifted to Second, First or Reverse (Replace Forward Sprag Assembly) Models: 1982 - 2005 GM Passenger Cars and Light Duty Trucks 2006 - 2007 Buick Rainier 2006 Cadillac Escalade, Escalade ESV, Escalade EXT 2006 Chevrolet SSR 2006 - 2008 Chevrolet Avalanche, Colorado, Express, Silverado Classic, Silverado, Suburban, Tahoe, TrailBlazer 2006 GMC Yukon Denali, Yukon Denali XL 2006 - 2008 GMC Canyon, Envoy, Savana, Sierra Classic, Sierra, Yukon, Yukon XL 2006 Pontiac GTO 2006 - 2007 HUMMER H2 2006 - 2008 HUMMER H3 2006 - 2008 Saab 9-7X with 4L60, 4L60E, 4L65E or 4L70E Automatic Transmission (RPOs MD8, M30, M32, M33 or M70) Condition Some customers may comment that the vehicle has no movement when the transmission is shifted to DRIVE or THIRD position, but there is normal operation when it is shifted to SECOND, FIRST or REVERSE position. Cause This condition may be caused by a damaged forward sprag assembly (642). Correction When inspecting the sprag, it is important to test the sprag for proper operation by holding the outer race (644) with one hand while rotating the input sun gear (640) with the other hand. The sun gear should rotate only in the counterclockwise direction with the input sun gear facing upward. If the sprag rotates in both directions or will not rotate in either direction, the sprag elements should be inspected by removing one of the sprag assembly retaining rings (643). Refer to SI Unit Repair section for forward clutch sprag disassembly procedures. If the sprag is found to be damaged, make repairs to the transmission as necessary. A new forward roller clutch sprag assembly is now available from GMSPO. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Clutch: > 08-07-30-027 > Jun > 08 > A/T - No Movement in Drive or 3rd Gear > Page 6119 If clutch debris is found, it is also very important to inspect the Pressure Control (PC) solenoid valve (377) fluid screens. Clean or replace the PC solenoid (377) as necessary. It is also important to flush and flow check the transmission oil cooler using J45096. Refer to SI Automatic Transmission Oil Cooler Flushing and Flow Test for the procedure. The notches above each sprag must point up as shown when assembled into the outer race. Bearing Assembly, Input Sun Gear Snap Ring, Overrun Clutch Hub Retaining Hub, Overrun Clutch Wear Plate, Sprag Assembly Retainer and Race Assembly, Sprag Forward Sprag Assembly Retainer Rings, Sprag Assembly Outer Race, Forward Clutch Washer, Thrust (Input Carrier to Race) The following information applies when this sprag is used in 1982-86 transmissions. The new design sprag can be used on models 1982 through 1986, by replacing the entire assembly (637 - 644). Individual components are NOT Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Clutch: > 08-07-30-027 > Jun > 08 > A/T - No Movement in Drive or 3rd Gear > Page 6120 interchangeable. Important: The wear plate (640) and input thrust washer (660) are not required with the new sprag. Use of the thrust washer and wear plate with the new sprag assembly will cause a misbuild (correct end play cannot be obtained). Parts Information Warranty Information For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Clutch: > 477141 > Jan > 95 > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Clutch: All Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Clutch: > 477141 > Jan > 95 > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6125 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Clutch: > 477141 > Jan > 95 > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6126 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Other Service Bulletins for Clutch: > 477141 > Jan > 95 > A/T 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Clutch: All Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Other Service Bulletins for Clutch: > 477141 > Jan > 95 > A/T 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6132 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Clutch, A/T > Component Information > Technical Service Bulletins > All Other Service Bulletins for Clutch: > 477141 > Jan > 95 > A/T 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6133 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information Fluid - A/T: Technical Service Bulletins A/T - DEXRON(R)-VI Fluid Information INFORMATION Bulletin No.: 04-07-30-037E Date: April 07, 2011 Subject: Release of DEXRON(R)-VI Automatic Transmission Fluid (ATF) Models: 2008 and Prior GM Passenger Cars and Light Duty Trucks 2003-2008 HUMMER H2 2006-2008 HUMMER H3 2005-2007 Saturn Relay 2005 and Prior Saturn L-Series 2005-2007 Saturn ION 2005-2008 Saturn VUE with 4T45-E 2005-2008 Saab 9-7X Except 2008 and Prior Chevrolet Aveo, Equinox Except 2006 and Prior Chevrolet Epica Except 2007 and Prior Chevrolet Optra Except 2008 and Prior Pontiac Torrent, Vibe, Wave Except 2003-2005 Saturn ION with CVT or AF23 Only Except 1991-2002 Saturn S-Series Except 2008 and Prior Saturn VUE with CVT, AF33 or 5AT (MJ7/MJ8) Transmission Only Except 2008 Saturn Astra Attention: DEXRON(R)-VI Automatic Transmission Fluid (ATF) is the only approved fluid for warranty repairs for General Motors transmissions/transaxles requiring DEXRON(R)-III and/or prior DEXRON(R) transmission fluids. Supercede: This bulletin is being revised to update information. Please discard Corporate Bulletin Number 04-07-30-037D (Section 07 - Transmission/Transaxle). MANUAL TRANSMISSIONS / TRANSFER CASES and POWER STEERING The content of this bulletin does not apply to manual transmissions or transfer cases. Any vehicle that previously required DEXRON(R)-III for a manual transmission or transfer case should now use P/N 88861800. This fluid is labeled Manual Transmission and Transfer Case Fluid. Some manual transmissions and transfer cases require a different fluid. Appropriate references should be checked when servicing any of these components. Power Steering Systems should now use P/N 9985010 labeled Power Steering Fluid. Consult the Parts Catalog, Owner's Manual, or Service Information (SI) for fluid recommendations. Some of our customers and/or General Motors dealerships/Saturn Retailers may have some concerns with DEXRON(R)-VI and DEXRON(R)-III Automatic Transmission Fluid (ATF) and transmission warranty claims. DEXRON(R)-VI is the only approved fluid for warranty repairs for General Motors transmissions/transaxles requiring DEXRON(R)-III and/or prior DEXRON(R) transmission fluids (except as noted above). Please remember that the clean oil reservoirs of the J-45096 - Flushing and Flow Tester machine should be purged of DEXRON(R)-III and filled with DEXRON(R)-VI for testing, flushing or filling General Motors transmissions/transaxles (except as noted above). DEXRON(R)-VI can be used in any proportion in past model vehicles equipped with an automatic transmission/transaxle in place of DEXRON(R)-III (i.e. topping off the fluid in the event of a repair or fluid change). DEXRON(R)-VI is also compatible with any former version of DEXRON(R) for use in automatic transmissions/transaxles. DEXRON(R)-VI ATF General Motors Powertrain has upgraded to DEXRON(R)-VI ATF with the start of 2006 vehicle production. Current and prior automatic transmission models that had used DEXRON(R)-III must now only use DEXRON(R)-VI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 6138 All 2006 and future model transmissions that use DEXRON(R)-VI are to be serviced ONLY with DEXRON(R)-VI fluid. DEXRON(R)-VI is an improvement over DEXRON(R)-III in the following areas: * These ATF change intervals remain the same as DEXRON(R)-III for the time being. 2006-2008 Transmission Fill and Cooler Flushing Some new applications of the 6L80 six speed transmission will require the use of the J 45096 Flushing and Flow Tester to accomplish transmission fluid fill. The clean oil reservoir of the machine should be purged of DEXRON(R)-III and filled with DEXRON(R)-VI. Parts Information Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 6139 Fluid - A/T: Technical Service Bulletins A/T - Water Or Coolant Contamination Information INFORMATION Bulletin No.: 08-07-30-035B Date: November 01, 2010 Subject: Information on Water or Ethylene Glycol in Transmission Fluid Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks with Automatic Transmission Supercede: This bulletin is being revised to update model years. Please discard Corporate Bulletin Number 08-07-30-035A (Section 07 - Transmission/Transaxle). Water or ethylene glycol in automatic transmission fluid (ATF) is harmful to internal transmission components and will have a negative effect on reliability and durability of these parts. Water or ethylene glycol in ATF will also change the friction of the clutches, frequently resulting in shudder during engagement or gear changes, especially during torque converter clutch engagement. Indications of water in the ATF may include: - ATF blowing out of the transmission vent tube. - ATF may appear cloudy or, in cases of extreme contamination, have the appearance of a strawberry milkshake. - Visible water in the oil pan. - A milky white substance inside the pan area. - Spacer plate gaskets that appear to be glued to the valve body face or case. - Spacer plate gaskets that appear to be swollen or wrinkled in areas where they are not compressed. - Rust on internal transmission iron/steel components. If water in the ATF has been found and the source of the water entry has not been identified, or if a leaking in-radiator transmission oil cooler is suspected (with no evidence of cross-contamination in the coolant recovery reservoir), a simple and quick test kit is available that detects the presence of ethylene glycol in ATF. The "Gly-Tek" test kit, available from the Nelco Company, should be obtained and the ATF tested to make an accurate decision on the need for radiator replacement. This can help to prevent customer comebacks if the in-radiator transmission oil cooler is leaking and reduce repair expenses by avoiding radiator replacement if the cooler is not leaking. These test kits can be obtained from: Nelco Company Test kits can be ordered by phone or through the website listed above. Orders are shipped standard delivery time but can be shipped on a next day delivery basis for an extra charge. One test kit will complete 10 individual fluid sample tests. For vehicles repaired under warranty, the cost of the complete test kit plus shipping charges should be divided by 10 and submitted on the warranty claim as a net item. The transmission should be repaired or replaced based on the normal cost comparison procedure. Important If water or coolant is found in the transmission, the following components MUST be replaced. - Replace all of the rubber-type seals. - Replace all of the composition-faced clutch plates and/or bands. - Replace all of the nylon parts. - Replace the torque converter. - Thoroughly clean and rebuild the transmission, using new gaskets and oil filter. Important The following steps must be completed when repairing or replacing. Flush and flow check the transmission oil cooler using J 45096. Refer to Corporate Bulletin Number 02-07-30-052F- Automatic Transmission Oil Cooler Flush and Flow Test Essential Tool J 45096 TransFlow. - Thoroughly inspect the engine cooling system and hoses and clean/repair as necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 6140 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 6141 Fluid - A/T: Technical Service Bulletins A/T - DEXRON III Fluid Introduction File In Section: 0 - General Information Bulletin No.: 57-02-01 Date: March, 1995 SERVICE MANUAL UPDATE Subject: Section 0 - General Information - DEXRON(R)-III Transmission Fluid Introduction Models: 1995 and Prior Passenger Cars and Trucks General Motors has phased in a new automatic transmission fluid, DEXRON(R)-III, that does not need replacing under normal service. DEXRON(R)-III is designed to help the transmission deliver the best possible performance under all conditions. Refer to Figure 1. The improvements in DEXRON(R)-III include better friction stability, more high temperature oxidation stability and better material compatibility. DEXRON(R)-III has the same low temperature fluidity as DEXRON(R)-IIE, for better transmission performance in cold weather. DEXRON(R)-IIE and DEXRON(R)-III are fully compatible. DEXRON(R)-III is fully compatible with any General Motors passenger vehicle or light truck with automatic transmission and built since 1949. Dealers should require their supplier to include the DEXRON(R)-III license number on all automatic transmission fluid invoices. Starting February 1, 1994 DEXRON(R)-III was phased into all North American assembly plants. DEXRON(R)-III fluid is available from GMSPO (see fluid numbers below): U.S. 1 Quart 12346143 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > A/T - DEXRON(R)-VI Fluid Information > Page 6142 1 Gallon 12346144 55 Gallon 12346145 In Canada 1 Liter 10952622 4 Liter 10952623 200 Liter 10952624 The 1995 Automatic Transmission/Transaxle fluid change intervals are the following: (1994 and prior should use the schedules as written in the Owner's Manual.) If the vehicle is mainly driven under one or more of these conditions: In heavy city traffic where the outside temperature regularly reaches 90°F (32°C) or higher. In hilly or mountainous terrain. When doing frequent trailer towing. Uses such as found in taxi, police car or delivery service. Change the fluid and filter every 50,000 miles (63,000 km). If the vehicle is not used mainly under any of these conditions, the fluid and filter do not require periodic changing for vehicles under 8,600 GVWR. Vehicles over 8,600 GVWR change the fluid and filter every 50,000 miles (83,000 km) regardless of driving conditions. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > Page 6143 Fluid - A/T: Specifications Fluid Type ........................................................................................................................................................ DEXRON-IIE or DEXRON-III auto. trans. Capacity Drain & Refill ........................................................................................................................................ .............................................. 4.7 liters (10.0 pt) Overhaul .................................................................. .......................................................................................................................... 10.6 liters (22.4 pt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Fluid - A/T > Component Information > Technical Service Bulletins > Page 6144 Fluid - A/T: Service and Repair NOTE: The following procedure has been modified by a technical service bulletin. 1. Raise and support vehicle. 2. Proceed as follows: a. Loosen transmission mount to support attaching nut. b. Loosen two bolts attaching right side of transmission support to frame rail. c. Remove two bolts attaching left side transmission support to frame rail. d. Using suitable transmission jack, support and slightly raise transmission. e. Slide transmission support rearward enough to access rear oil pan attaching bolts. 3. Place drain pan under transmission oil pan, loosen pan bolts on front of pan, pry carefully with screwdriver to loosen oil pan, and allow fluid to drain. 4. Remove remaining oil pan bolts, oil pan, and gasket. 5. Drain fluid from pan, then clean pan and dry thoroughly with compressed air. 6. Remove oil filter to valve body bolt, then the filter and gasket. 7. Install new filter seal into case, then new filter and attaching bolt. 8. Install new gasket on oil pan, then install oil pan and tighten bolts to specification. 9. Lower vehicle and add five quarts of automatic transmission fluid through filler tube. 10. With selector lever in park and parking brake applied, start engine and let idle. Do not race engine. 11. Move selector lever through each range, return to park position, check fluid, and add additional fluid to bring level between dimples on dipstick. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6154 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6155 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6156 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6162 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6163 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6164 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 6165 Shift Indicator: Description and Operation DESCRIPTION This lamp is used on most models equipped with manual transmission. OPERATION The Upshift lamp is illuminated to inform the driver of ideal shift points, with improved fuel economy as the specific objective. When the light is illuminated, the transmission should be shifted to the next highest gear, if driving conditions permit such an action. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Lamps and Indicators A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 6166 Shift Indicator: Service and Repair If upshift indicator is not working properly, perform the following test. 1. Disconnect ECM connector C1. 2. Place ignition switch in run. 3. Measure voltage at terminal A2 of ECM connector. 4. If battery voltage is present, further ECM diagnosis is necessary. 5. If battery voltage is not present, repair open circuit in brown/black wire, circuit 456. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Output Shaft, A/T > Component Information > Technical Service Bulletins > A/T - 2-3 Upshift or 3-2 Downshift Clunk Noise Output Shaft: Technical Service Bulletins A/T - 2-3 Upshift or 3-2 Downshift Clunk Noise INFORMATION Bulletin No.: 01-07-30-042F Date: February 05, 2010 Subject: Information on 2-3 Upshift or 3-2 Downshift Clunk Noise Models: 2010 and Prior GM Passenger Cars and Light Duty Trucks 2010 and Prior HUMMER H2, H3 2005-2009 Saab 9-7X with 4L60-E, 4L65-E or 4L70-E Automatic Transmission (RPOs M30, M32, M70) Supercede: This bulletin is being revised to add the 2010 model year and 4L70E transmission. Please discard Corporate Bulletin Number 01-07-30-042E (Section 07 - Transmission/Transaxle). Important For 2005 model year fullsize utilities and pickups, refer to Corporate Bulletin 05-07-30-012. Some vehicles may exhibit a clunk noise that can be heard on a 2-3 upshift or a 3-2 downshift. During a 2-3 upshift, the 2-4 band is released and the 3-4 clutch is applied. The timing of this shift can cause a momentary torque reversal of the output shaft that results in a clunk noise. This same torque reversal can also occur on a 3-2 downshift when the 3-4 clutch is released and the 2-4 band applied. This condition may be worse on a 4-wheel drive vehicle due to the additional tolerances in the transfer case. This is a normal condition. No repairs should be attempted. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Parking Pawl, A/T > Component Information > Technical Service Bulletins > A/T - Grinding/Growling Noise in Park on Incline Parking Pawl: Technical Service Bulletins A/T - Grinding/Growling Noise in Park on Incline INFORMATION Bulletin No.: 99-07-30-030F Date: May 01, 2008 Subject: Grinding and/or Growling Noise in Park on Incline Models: 2009 and Prior Passenger Cars and Light Duty Trucks (Including Saturn) with Hydra-Matic Front Wheel Drive (FWD) Automatic Transmissions Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 99-07-30-030E (Section 07 - Transmission/Transaxle). Service Information Owners of some vehicles equipped with Hydra-Matic front wheel drive transaxles may comment on a grinding and/or growling noise that is noticeable when standing in PARK on a hill or slope with the engine running and the parking brake not applied. Under these conditions, the weight of the vehicle puts a load on the parking pawl which can create a "ground-out" path through the drive axles, front struts, springs and spring towers. Normal engine noise can be transmitted to the passenger compartment through the "ground-out" path. Owners concerned about this condition should be advised to apply the parking brake prior to shifting into PARK. This is the recommended procedure described in the Owners Manual. Applying the parking brake first will put the load of the vehicle on the rear brakes rather than on the parking pawl. Refer the owner to the appropriate Owner Manual for additional details and instructions. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6180 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6181 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6184 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6185 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6186 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6187 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6188 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6189 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6190 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6191 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6192 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6193 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6194 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6195 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6196 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6197 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6198 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6199 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6200 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6201 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6202 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6203 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6204 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6205 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6206 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6207 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6208 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6209 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6210 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6211 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6212 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6213 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6214 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6215 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 6216 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Temperature Sensor/Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6221 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6222 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6223 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6224 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6225 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6226 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6227 Transmission Temperature Sensor/Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6228 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6229 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6230 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6231 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6232 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6233 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6234 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6235 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6236 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6237 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6238 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6239 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6240 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6241 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6242 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6243 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6244 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6245 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6246 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6247 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6248 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6249 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6250 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6251 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6252 Transmission Range Switch Assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sensors and Switches A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Page 6253 Transmission Temperature Sensor/Switch: Description and Operation The Transmission Fluid Temperature (TFT) sensor is a thermistor (a device that changes resistance according to changes in temperature) used to indicate transmission fluid temperature. High sensor resistance produces high signal input voltage which corresponds to low fluid temperature. Low sensor resistance produces low signal input voltage which corresponds to high fluid temperature. The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following: ^ Torque Converter Clutch (TCC) apply and release schedules. ^ Hot mode determination. ^ Shift quality. The TFT sensor is part of the transmission range fluid pressure switch assembly and is attached to the control valve body within the transmission. A fault in the Transmission Fluid Temperature (TFT) sensor circuit will set a DTC 58. 59 or 79. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Locations Shift Interlock: Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Locations > Page 6257 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions Shift Interlock: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6260 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6261 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6262 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6263 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6264 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6265 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6266 Shift Interlock: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6267 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6268 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6269 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6270 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6271 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6272 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6273 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6274 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6275 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6276 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6277 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6278 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6279 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6280 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6281 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6282 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6283 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6284 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6285 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6286 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6287 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6288 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6289 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6290 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6291 Brake Transmission Shift Interlock (BTSI) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Diagrams > Page 6292 Shift Interlock: Description and Operation The Backup Lamp Transmission Position Sensor Switch receives Ignition voltage from I/P Fuse #12 in "RUN," "BULB TEST" and "START." When the Transmission Shift Lever is in "PARK," the switch relays voltage to the Brake Transmission Shift Interlock (BTSI) Switch. The BTSI Switch is normally closed, providing voltage to the BTSI Solenoid, which is permanently grounded at G200. When the BTSI Solenoid receives voltage, it is energized and prevents the Transmission Shift Lever from being moved out of "PARK." When the brake pedal is depressed, the BTSI Switch opens, removing voltage from the BTSI Solenoid. This de-energizes the Solenoid, allowing operation of the Shift Lever. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Shift Interlock: Initial Inspection and Diagnostic Overview Circuit Operation - Brake Transaxle Shift Interlock The Backup Lamp Transmission Position Sensor Switch receives Ignition voltage from I/P Fuse #12 in "RUN," "BULB TEST" and "START." When the Transmission Shift Lever is in "PARK," the switch relays voltage to the Brake Transmission Shift Interlock (BTSI) Switch. The BTSI Switch is normally closed, providing voltage to the BTSI Solenoid, which is permanently grounded at G200. When the BTSI Solenoid receives voltage, it is energized and prevents the Transmission Shift Lever from being moved out of "PARK." When the brake pedal is depressed, the BTSI Switch opens, removing voltage from the BTSI Solenoid. This de-energizes the Solenoid, allowing operation of the Shift Lever. Troubleshooting Hints - Brake Transaxle Shift Interlock PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: 1. Check I/P Fuse Block Fuse #12. If open, check CKT 239, CKT 275 and CKT 924 for a short to ground. 2. Make sure G200 is clean and tight. 3. If Transmission Shift Lever does not shift out of Park, make sure the linkage is properly adjusted. ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids ^ Refer to System Diagnosis. See: Component Tests and General Diagnostics Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 6295 Shift Interlock: Symptom Related Diagnostic Procedures Symptom Table Chart #1 TRANS Does Not Shift Out Of Park W/Brake Pedal Depressed Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Interlock, A/T > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 6296 Chart #2 TRANS Shifts Out Of Park With Ignition Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Shift Linkage, A/T > Component Information > Adjustments Shift Linkage: Adjustments Fig.6 Shift Linkage Adjustment. ADJUSTMENTS 1. Loosen swivel clamp screw. 2. Position shift lever in neutral gate. 3. Position transmission lever in neutral detent. 4. While holding swivel clamp flush against equalizer lever, tighten swivel clamp screw, Fig. 6. Do not exert force in either direction on rod or equalizer lever while tightening swivel clamp screw. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sun Gear > Component Information > Technical Service Bulletins > Customer Interest for Sun Gear: > 00-07-30-022D > Jun > 08 > A/T - 4L60/65E, No Reverse/2nd or 4th Gear Sun Gear: Customer Interest A/T - 4L60/65E, No Reverse/2nd or 4th Gear TECHNICAL Bulletin No.: 00-07-30-022D Date: June 10, 2008 Subject: No Reverse, Second Gear or Fourth Gear (Replace Reaction Sun Shell with More Robust Heat Treated Parts) Models: 1993 - 2005 GM Passenger Cars and Light Duty Trucks 2003 - 2005 HUMMER H2 with 4L60/65-E Automatic Transmission (RPOs M30 or M32) Supercede: This bulletin is being revised to add 2005 model year to the parts information. Please discard Corporate Bulletin Number 00-07-30-022C (Section 07 - Transmission/Transaxle). Condition Some customers may comment on a no reverse, no second or no fourth gear condition. First and third gears will operate properly. Cause The reaction sun gear (673) may not hold inside the reaction sun shell (670). Correction Important: There are FOUR distinct groups of vehicles and repair procedures involved. Vehicles built in the 2001 model year and prior that make use of a reaction shaft to shell thrust washer: ^ The sun shell can be identified by four square holes used to retain the thrust washer. Use reaction sun shell P/N 24228345, reaction carrier to shell thrust washer (699B) P/N 8642202 and reaction sun gear shell thrust washer (674) P/N 8642331er (674) P/N 8642331along with the appropriate seals and washers listed below. ^ Vehicles built in the 2001 model year and prior that have had previous service to the reaction sun shell: It is possible that some 2001 and prior model year vehicles have had previous service to the reaction sun shell. At the time of service, these vehicles may have been updated with a Reaction Sun Shell Kit (Refer to Service Bulletin 020730003) without four square holes to retain the thrust washer. If it is found in a 2001 model year and prior vehicles that the reaction sun shell DOES NOT have four square holes to retain the thrust washer, these vehicles must be serviced with P/Ns 24229825 (674), 24217328 and 8642331 along with the appropriate seals and washers listed below. ^ Vehicles built in the 2001 model year and later that make use of a reaction shaft to shell thrust bearing: The sun shell can be identified by no holes to retain the thrust washer. Use reaction sun shell, P/N 24229825, reaction carrier shaft to shell thrust bearing (669A), P/N 24217328 and reaction sun gear shell thrust washer (674), P/N 8642331 along with the appropriate seals and washers listed below. ^ Vehicles built from November, 2001 through June, 2002: These vehicles should have the reaction carrier shaft replaced when the sun shell is replaced. Use shell kit P/N 24229853, which contains a sun shell (670), a reaction carrier shaft (666), a reaction carrier shaft to shell thrust bearing (669A) and a reaction sun gear shell thrust washer (674). The appropriate seals and washers listed below should also be used. When servicing the transmission as a result of this condition, the transmission oil cooler and lines MUST be flushed. Refer to Corporate Bulletin Number 02-07-30-052. Follow the service procedure below for diagnosis and correction of the no reverse, no second, no forth condition. Important: If metallic debris is found on the transmission magnet, the transmission must be completely disassembled and cleaned. Metallic debris is defined as broken parts and pieces of internal transmission components. This should not be confused with typical "normal" fine particles found on all transmission magnets. Failure to properly clean the transmission case and internal components may lead to additional repeat repairs. 1. Remove the transmission oil pan and inspect the magnet in the bottom of the pan for metal debris. Refer to SI Document ID # 825141. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sun Gear > Component Information > Technical Service Bulletins > Customer Interest for Sun Gear: > 00-07-30-022D > Jun > 08 > A/T - 4L60/65E, No Reverse/2nd or 4th Gear > Page 6308 2. Remove the transmission from the vehicle. Refer to the appropriate SI document. Important: ^ Inspect all the transmission components for damage or wear. Replace all damaged or worn components. The parts shown above should be sufficient to correct this concern. ^ This condition does not normally require replacement of the transmission completely. Components such as clutches, valve body, pump and torque converters will NOT require replacement to correct this condition. Disassemble the transmission and replace the appropriate parts listed below. Refer to the Unit Repair Manual - Repair Instructions. 3. Reinstall the transmission in the vehicle. Refer to appropriate service information. When servicing the transmission as a result of this condition, the transmission oil cooler and lines MUST be flushed. Refer to Corporate Bulletin Number 02-07-30-052. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sun Gear > Component Information > Technical Service Bulletins > Customer Interest for Sun Gear: > 00-07-30-022D > Jun > 08 > A/T - 4L60/65E, No Reverse/2nd or 4th Gear > Page 6309 Parts Information Warranty Information For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sun Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Sun Gear: > 00-07-30-022D > Jun > 08 > A/T - 4L60/65E, No Reverse/2nd or 4th Gear Sun Gear: All Technical Service Bulletins A/T - 4L60/65E, No Reverse/2nd or 4th Gear TECHNICAL Bulletin No.: 00-07-30-022D Date: June 10, 2008 Subject: No Reverse, Second Gear or Fourth Gear (Replace Reaction Sun Shell with More Robust Heat Treated Parts) Models: 1993 - 2005 GM Passenger Cars and Light Duty Trucks 2003 - 2005 HUMMER H2 with 4L60/65-E Automatic Transmission (RPOs M30 or M32) Supercede: This bulletin is being revised to add 2005 model year to the parts information. Please discard Corporate Bulletin Number 00-07-30-022C (Section 07 - Transmission/Transaxle). Condition Some customers may comment on a no reverse, no second or no fourth gear condition. First and third gears will operate properly. Cause The reaction sun gear (673) may not hold inside the reaction sun shell (670). Correction Important: There are FOUR distinct groups of vehicles and repair procedures involved. Vehicles built in the 2001 model year and prior that make use of a reaction shaft to shell thrust washer: ^ The sun shell can be identified by four square holes used to retain the thrust washer. Use reaction sun shell P/N 24228345, reaction carrier to shell thrust washer (699B) P/N 8642202 and reaction sun gear shell thrust washer (674) P/N 8642331er (674) P/N 8642331along with the appropriate seals and washers listed below. ^ Vehicles built in the 2001 model year and prior that have had previous service to the reaction sun shell: It is possible that some 2001 and prior model year vehicles have had previous service to the reaction sun shell. At the time of service, these vehicles may have been updated with a Reaction Sun Shell Kit (Refer to Service Bulletin 020730003) without four square holes to retain the thrust washer. If it is found in a 2001 model year and prior vehicles that the reaction sun shell DOES NOT have four square holes to retain the thrust washer, these vehicles must be serviced with P/Ns 24229825 (674), 24217328 and 8642331 along with the appropriate seals and washers listed below. ^ Vehicles built in the 2001 model year and later that make use of a reaction shaft to shell thrust bearing: The sun shell can be identified by no holes to retain the thrust washer. Use reaction sun shell, P/N 24229825, reaction carrier shaft to shell thrust bearing (669A), P/N 24217328 and reaction sun gear shell thrust washer (674), P/N 8642331 along with the appropriate seals and washers listed below. ^ Vehicles built from November, 2001 through June, 2002: These vehicles should have the reaction carrier shaft replaced when the sun shell is replaced. Use shell kit P/N 24229853, which contains a sun shell (670), a reaction carrier shaft (666), a reaction carrier shaft to shell thrust bearing (669A) and a reaction sun gear shell thrust washer (674). The appropriate seals and washers listed below should also be used. When servicing the transmission as a result of this condition, the transmission oil cooler and lines MUST be flushed. Refer to Corporate Bulletin Number 02-07-30-052. Follow the service procedure below for diagnosis and correction of the no reverse, no second, no forth condition. Important: If metallic debris is found on the transmission magnet, the transmission must be completely disassembled and cleaned. Metallic debris is defined as broken parts and pieces of internal transmission components. This should not be confused with typical "normal" fine particles found on all transmission magnets. Failure to properly clean the transmission case and internal components may lead to additional repeat repairs. 1. Remove the transmission oil pan and inspect the magnet in the bottom of the pan for metal debris. Refer to SI Document ID # 825141. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sun Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Sun Gear: > 00-07-30-022D > Jun > 08 > A/T - 4L60/65E, No Reverse/2nd or 4th Gear > Page 6315 2. Remove the transmission from the vehicle. Refer to the appropriate SI document. Important: ^ Inspect all the transmission components for damage or wear. Replace all damaged or worn components. The parts shown above should be sufficient to correct this concern. ^ This condition does not normally require replacement of the transmission completely. Components such as clutches, valve body, pump and torque converters will NOT require replacement to correct this condition. Disassemble the transmission and replace the appropriate parts listed below. Refer to the Unit Repair Manual - Repair Instructions. 3. Reinstall the transmission in the vehicle. Refer to appropriate service information. When servicing the transmission as a result of this condition, the transmission oil cooler and lines MUST be flushed. Refer to Corporate Bulletin Number 02-07-30-052. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Sun Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Sun Gear: > 00-07-30-022D > Jun > 08 > A/T - 4L60/65E, No Reverse/2nd or 4th Gear > Page 6316 Parts Information Warranty Information For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Torque Converter > Component Information > Technical Service Bulletins > A/T - Torque Converter Replacement Information Torque Converter: Technical Service Bulletins A/T - Torque Converter Replacement Information INFORMATION Bulletin No.: 01-07-30-010C Date: May 12, 2008 Subject: Automatic Transmission/Transaxle Torque Converter Replacement Models: 2009 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2, H3 2009 and Prior Saturn Cars and Light Duty Trucks (Except VTi Equipped Vehicles (RPO M16 and M75) 2009 and Prior Saab 9-7X with ALL Automatic Transmissions and Transaxles Supercede: This bulletin is being revised to add the 2007-2009 model years. Please discard Corporate Bulletin Number 01-07-30-010B (Section 07 - Transmission/Transaxle). The purpose of this bulletin is to help technicians determine when a torque converter should be replaced. Below is a list of general guidelines to follow. The converter should NOT be replaced if the following apply: ^ DTC P0742 - TCC stuck on is set. This code is almost always the result of a controls condition (i.e. stuck TCC solenoid/valve). Experience has shown that this code rarely indicates a mechanical concern within the torque converter. ^ The fluid has an odor or is discolored but no evidence of metal contamination. ^ Fine metal particles (traces of metal flakes/gray color to fluid ) are found in the converter. This is not harmful to the torque converter. ^ The vehicle has been exposed to high mileage. ^ A small amount of wear appears on the hub where the oil pump drive gear mates to the converter (RWD only). A certain amount of such wear is normal for both the hub and oil pump gear. Neither the converter nor the front pump assembly should be replaced. The torque converter should be replaced under any of the following conditions: ^ The vehicle has TCC shudder and/or no TCC apply. First complete all electrical and hydraulic diagnosis and check for proper engine operation. The converter clutch may be damaged. Also the converter bushing and/or internal 0-ring may be damaged. ^ Evidence of damage to the oil pump assembly pump shaft turbine shaft drive sprocket support and bearing or metal chips/debris in the converter. ^ Metal chips/debris are found in the converter or when flushing the cooler and the cooler lines. ^ External leaks in the hub weld area lug weld or closure weld. ^ Converter pilot is broken damaged or fits poorly into the crankshaft. ^ The converter hub is scored or damaged. ^ The transmission oil is contaminated with engine coolant engine oil or water. ^ If excessive end play is found after measuring the converter for proper end play (refer to Service Manual). ^ If metal chips/debris are found in the fluid filter or on the magnet and no internal parts in the unit are worn or damaged. This indicates that the material came from the converter. ^ The converter has an unbalanced condition that results in a vibration that cannot be corrected by following Converter Vibration Procedures. ^ Blue converter or dark circular ring between lugs. This condition will also require a complete cleaning of the cooler and a check for adequate flow Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Torque Converter > Component Information > Technical Service Bulletins > A/T - Torque Converter Replacement Information > Page 6321 through the cooler. ^ Converter bearing noise determined by noise from the bell housing area in Drive or Reverse at idle. The noise is gone in Neutral and Park. ^ If silicon from the viscous clutch is found in the lower pan (4T80-E ONLY). Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Torque Converter Clutch Solenoid: Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6326 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6327 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > Page 6328 Torque Converter Clutch Solenoid: Service and Repair REPLACE 1. Raise and support vehicle. 2. Disconnect heated oxygen sensor. 3. Remove catalytic converter to muffler attaching bolts and nuts. 4. Remove catalytic converter hanger to catalytic converter bolts. 5. Remove righthand side dampener assembly. 6. Remove nuts holding exhaust pipe to exhaust manifold. 7. Remove converter and pipe assembly from vehicle. 8. Remove oil pan and oil filter assembly. 9. Disconnect external wiring harness from transmission pass through connector. 10. Remove accumulator cover attaching bolts. 11. Remove 1-2 accumulator cover, piston and spring. 12. Disconnect electrical connectors. 13. Remove pressure control solenoid retainer bolt, then the retainer and solenoid. 14. Remove TCC solenoid retaining bolts. 15. Remove pass-through electrical connector from transmission case by positioning the small end of power piston seal protector and diaphragm retainer installer tool No. J-28458 or equivalent, over the top of the connector, then twist tool to release the four tabs while at the same time pulling the harness through the case. 16. Remove TCC solenoid with wiring harness from transmission case. 17. Reverse procedure to install, noting the following: a. Tighten TCC solenoid retaining bolt to specification. b. Tighten pressure control solenoid retaining bolt to specification. c. When installing 1-2 accumulator piston to accumulator cover, the piston legs must face towards the case. d. Tighten accumulator attaching bolts to specification Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Cooler, A/T > Component Information > Technical Service Bulletins > A/T - Fluid Oil Cooler Flush Transmission Cooler: Technical Service Bulletins A/T - Fluid Oil Cooler Flush INFORMATION Bulletin No.: 02-07-30-052G Date: March 02, 2011 Subject: Automatic Transmission Oil Cooler Flush and Flow Test Essential Tool J 45096 TransFlow(R) Models: 2011 and Prior Passenger Cars and Light Duty Trucks 2003-2010 HUMMER H2 2006-2010 HUMMER H3 with Automatic Transmission/Transaxle including Allison(R) Transmissions Supercede: This bulletin is being revised to update the model years. Please discard Corporate Bulletin Number 02-07-30-052F (Section 07 - Transmission/Transaxle). Important All labor operations that include removal of the transmission from the vehicle include labor time to flush the transmission oil cooler system. The J 45096 transmission oil cooling system flush and flow test tool replaces current tool J 35944-A. J 45096 is a self-contained unit utilizing a 12-volt flow meter, shop air supply and DEXRON(R) VI automatic transmission fluid (ATF). In the flush mode, transmission fluid is cycled through the transmission oil cooling system. High-pressure air is automatically injected into the fluid stream adding agitation to the ATF oil to enhance the removal of contaminated ATF oil and debris. In the flow mode, an electronic flow meter is used to measure the flow capability of the ATF oil cooling system. A digital display indicates the ATF oil flow rate in gallons per minute (GPM) along with the amount of ATF oil in the supply vessel, supply vessel ATF oil temperature, machine cycles and the operating mode. The supply oil vessel has 30 L (32 qt) capacity and the waste oil vessel has 32 L (34 qt) capacity. The waste oil vessel is constructed of a translucent composite material that allows the user to easily identify the oil level. The waste oil vessel can accommodate vacuum evacuation and gravity draining. In the code mode, a random, encrypted code is generated that can be used for verification of flow test results. Current essential cooler line adapters are used to connect the J 45096 to the automatic transmission oil cooler lines that allows J 45096 to adapt to General Motors passenger cars and light duty trucks, current and past models (except the Pontiac Vibe, Wave and Chevrolet Aveo). The tool may be adapted for use on the Pontiac Vibe, Wave and Chevrolet Aveo by dealership personnel with a barbed hose connector and rubber hose obtained locally. The Vibe's/Wave's/Aveo's transmission has a transmission oil requirement which is slightly different than DEXRON(R) VI ATF. However, flushing the cooler with DEXRON(R) VI automatic transmission fluid is an acceptable service procedure. Very little fluid remains in the cooler after the flush procedure and the residual DEXRON(R) VI ATF in the cooler is compatible with the Vibe's/Wave's/Aveo's transmission fluid. Notice Insufficient oil flow through the ATF oil cooling system will cause premature transmission failure. The required minimum ATF oil flow rate reading is directly related to the supply oil temperature. Refer to the flow rate reference chart for the oil flow rate specification based on the temperature of the ATF in the supply vessel. Helpful Hints for Maintaining the Temperature at or above 18°C (65°F) Important - The temperature of the supply vessel oil must be 18°C (65°F) or greater for J 45096 to operate. It is recommended to store the J 45096 in an area of the dealership where the room temperature remains at or above 18°C (65°F) when not in use. - Do not attempt to increase the fluid temperature in the Transflow(R) machine with an engine oil dipstick, or any other immersion type heater. The Transflow(R) machine has a check valve in the supply reservoir. Inserting a heater will damage the check valve and the subsequent repair expense would be the dealer's responsibility. - A heater blanket, P/N J-45096-10, is available for the Transflow(R) transmission cooling system flushing tool. This heater fastens around the Transflow(R) internal supply vessel and runs on 110 volts AC. The heater will warm the ATF in the supply vessel to at least 18°C (65° F) and has a thermostat to hold a constant temperature. Store the Transmission Cooling System Service Tool, J 45096, Transflow(R) machine in a room where the temperature is maintained at or above 18°C (65°F). Keep the ATF level in the reservoir low when the Transmission Cooling System Service Tool, J 45096, Transflow(R), is not in use. Store several gallons of oil in an area where the temperature is maintained at or above 18°C (65°F). Fill the reservoir of the J 45096 as needed before using the machine on Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Cooler, A/T > Component Information > Technical Service Bulletins > A/T - Fluid Oil Cooler Flush > Page 6333 each repair. With the ATF in a tightly sealed container, place the container in a tub of hot water for a period of time. Then pour the ATF into the reservoir. This method works best with a low fluid level in the reservoir. Place the Transflow(R) machine in the direct sunlight with the cabinet door open to expose the reservoir to the rays of the warm sun. Flush / Flow Test Procedure Important All labor operations that include removal of the transmission from the vehicle and require the transmission oil pan or transmission side cover to be removed include labor time to flush the transmission oil cooler system. Refer to SI for Automatic Transmission Oil Cooler Flushing and Flow Test J 45096 for the appropriate procedure. Important The J 45096 can be used to flush the transmission oil cooler system on an Allison equipped vehicle, but the flow meter should not be utilized. Refer to SI for Automatic Transmission Oil Cooler Flushing and Flow Test J 45096 for the appropriate flow check procedure. Machine Displays After completion of the flush and flow test, the following information is to be recorded on the repair order. This information is displayed on the Transmission Cooling System Service Tool, J 45096, Transflow(R) machine when the dial is in the code position. - Tested flow rate (displayed in Gallons Per Minute (GPM) - Temperature (displayed is degrees Fahrenheit) - Cycle number (a number) - Seven digit Alpha/Numeric flow code (i.e. A10DFB2) Warranty Information Important All labor operations that include removal of the transmission from the vehicle include labor time to flush the transmission oil cooler system. Performing a transmission oil cooling system flush and flow test will use between 4.7-7.5 L (5-8 qts) of DEXRON(R)VI transmission fluid. The amount Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Cooler, A/T > Component Information > Technical Service Bulletins > A/T - Fluid Oil Cooler Flush > Page 6334 of transmission fluid (ATF), (DEXRON(R)VI) (fluid) that is to be charged for the flush portion of the repair should not exceed the allowable charge for 7.5 L (2 gal) of fluid. This expense should be shown in the Parts Section of the warranty claim document. The Seven digit Alpha/Numeric flow code, i.e. A10DFB2, "MUST" be written on the job card and placed in the comments section of the warranty claim. Any repair that requires the technician to contact the Product Quality Center (PQC) must also include the seven digit flow code. The agent will request the seven digit flow code and add the information to the PQC case prior to providing authorization for the warranty claim. The Seven digit Alpha/Numeric flow code, i.e. A10DFB2, "MUST" be written on the job card, entered in the warranty claim labor operation Flush Code additional field (when available) and placed in the comments section of the warranty claim. Any repair that requires the technician to contact the Product Quality Center (PQC) must also include the seven digit flow code. The agent will request the seven digit flow code and add the information to the PQC case prior to providing authorization for the warranty claim. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Cooler, A/T > Component Information > Technical Service Bulletins > A/T - Fluid Oil Cooler Flush > Page 6335 Transmission Cooler: Technical Service Bulletins A/T - Water Or Coolant Contamination Information INFORMATION Bulletin No.: 08-07-30-035B Date: November 01, 2010 Subject: Information on Water or Ethylene Glycol in Transmission Fluid Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks with Automatic Transmission Supercede: This bulletin is being revised to update model years. Please discard Corporate Bulletin Number 08-07-30-035A (Section 07 - Transmission/Transaxle). Water or ethylene glycol in automatic transmission fluid (ATF) is harmful to internal transmission components and will have a negative effect on reliability and durability of these parts. Water or ethylene glycol in ATF will also change the friction of the clutches, frequently resulting in shudder during engagement or gear changes, especially during torque converter clutch engagement. Indications of water in the ATF may include: - ATF blowing out of the transmission vent tube. - ATF may appear cloudy or, in cases of extreme contamination, have the appearance of a strawberry milkshake. - Visible water in the oil pan. - A milky white substance inside the pan area. - Spacer plate gaskets that appear to be glued to the valve body face or case. - Spacer plate gaskets that appear to be swollen or wrinkled in areas where they are not compressed. - Rust on internal transmission iron/steel components. If water in the ATF has been found and the source of the water entry has not been identified, or if a leaking in-radiator transmission oil cooler is suspected (with no evidence of cross-contamination in the coolant recovery reservoir), a simple and quick test kit is available that detects the presence of ethylene glycol in ATF. The "Gly-Tek" test kit, available from the Nelco Company, should be obtained and the ATF tested to make an accurate decision on the need for radiator replacement. This can help to prevent customer comebacks if the in-radiator transmission oil cooler is leaking and reduce repair expenses by avoiding radiator replacement if the cooler is not leaking. These test kits can be obtained from: Nelco Company Test kits can be ordered by phone or through the website listed above. Orders are shipped standard delivery time but can be shipped on a next day delivery basis for an extra charge. One test kit will complete 10 individual fluid sample tests. For vehicles repaired under warranty, the cost of the complete test kit plus shipping charges should be divided by 10 and submitted on the warranty claim as a net item. The transmission should be repaired or replaced based on the normal cost comparison procedure. Important If water or coolant is found in the transmission, the following components MUST be replaced. - Replace all of the rubber-type seals. - Replace all of the composition-faced clutch plates and/or bands. - Replace all of the nylon parts. - Replace the torque converter. - Thoroughly clean and rebuild the transmission, using new gaskets and oil filter. Important The following steps must be completed when repairing or replacing. Flush and flow check the transmission oil cooler using J 45096. Refer to Corporate Bulletin Number 02-07-30-052F- Automatic Transmission Oil Cooler Flush and Flow Test Essential Tool J 45096 TransFlow. - Thoroughly inspect the engine cooling system and hoses and clean/repair as necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Cooler, A/T > Component Information > Technical Service Bulletins > A/T - Fluid Oil Cooler Flush > Page 6336 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Cooler, A/T > Component Information > Technical Service Bulletins > A/T - Fluid Oil Cooler Flush > Page 6337 Transmission Cooler: Technical Service Bulletins A/T - Oil Cooler Flushing Frequently Asked Questions File In Section: 07 - Transmission/Transaxle Bulletin No.: 03-07-30-027 Date: June, 2003 INFORMATION Subject: Most Frequently Asked Questions and Answers for J 45096 TransFlow Transmission Oil Cooling System Flushing Machine Models: 2004 and Prior Passenger Cars and Light Duty Trucks with Automatic Transmission/Transaxle 2004 and Prior HUMMER H2 This bulletin is issued to help answer the most frequently asked questions and concerns about essential tool J 45096. Q: Why doesn't the machine work below 18°C (65°F)? A: The flow characteristics of ATF at temperatures below 18°C (65°F) does not provide accurate flow test results with the electronics used in the J 45096. Q: Why didn't the unit come with a tank heater? A: The vast majority of dealerships do not require a heater to keep the ATF above 18°C (65°F). As a result, the heater was deleted as a cost-savings measure. A tank heater, J 45096-10, is currently available from Kent-Moore if your dealership requires it. Refer to Corporate Bulletin Number 03-07-30-002A for suggestions on warming the ATF without using a heater blanket. Q: Why does the machine fail new oil coolers? A: Several reasons have been found. The most likely reason is the air pressure at the air hose connected to the J 45096 is less than 586 kPa (85 psi). Other reasons include a twisted hose inside the J 45096 at the bulkhead as a result of the nut turning when the waste or supply hose was installed, the internal pressure regulator was improperly set at the factory or a problem with the cooler lines on the vehicle. Perform the J 45096 self-test as described on pages 9 and 10 of the Operation Manual. If a problem is still detected, refer to Troubleshooting on page 19 of the Operation Manual. If a problem still persists, contact Kent-Moore Customer Service at 1-800-345-2233. Q: What is the difference between steel and aluminum oil coolers? A: The aluminum oil cooler tube is slightly thinner in construction than the steel oil cooler tube, which affects the oil flow rate. The fitting that is protruding out of the radiator tank easily identifies the aluminum oil cooler. Refer to the Quick Reference card provided with the J 45096 in order to identify the proper flow rate for the aluminum oil cooler. Q: Why can't I use TransFlow for Allison transmission cooling Systems? A: Validation of TransFlow is currently under development for light duty trucks equipped with the Allison automatic transmission. TransFlow is based on the existing MINIMUM flow rate specification through the transmission oil cooling system. The Allison transmission oil cooling system only has MAXIMUM oil flow rates specified and J 45096 does not have the capability to test the transmission oil cooling system at the maximum oil flow rate specification. Q: Why doesn't GM publish a specification for auxiliary transmission oil coolers? A: The auxiliary oil cooler used with GM vehicles does not contain an internal turbulator plate like the radiator tank oil cooler does. Therefore, there is no internal restriction that would affect the flow rate through the oil cooling system so a specification for auxiliary oil cooler is not required. Keep in mind, kinks and damage to the auxiliary cooler and lines can affect the flow rate through the system. Q: Why did GM drop the labor time for transmission repairs? A: The labor for flushing and flow testing the transmission oil cooling system is included with the R&R; labor of the "K" labor operations that require transmission removal. The time required to use the J 45096 to perform the flush and flow test is much less than that of the J 35944-A. The warranty labor savings allowed GM to provide the J 45096 at no cost to dealerships. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Cooler, A/T > Component Information > Technical Service Bulletins > A/T - Fluid Oil Cooler Flush > Page 6338 Q: Why didn't the machine come with the adapters to hook up to the car? A: The J 45096 was designed to use the previously released essential cooler line adapters for the J 35944-A. All adapters are listed on page 17 of the Operation Manual and can be ordered from Kent-Moore at 1-800-345-2233. Q: How do I connect the J 45096 to a Catera, Prizm or a Vibe? A: These vehicles, along with many other models, only require barbed fittings to connect to the rubber cooler hose. These fittings are commercially available and already found in many shops. Q: Why didn't I receive an Operation Manual with the machine? A: The Operation Manual was packaged in the upper portion of the shipping carton. If the shipping carton was lifted off the base without opening the top of the carton, the Operation Manual could have been discarded with the carton. Replacement Operation Manual packages can be obtained from Kent-Moore Customer Service at 1-800-345-2233. Q: Why can't I re-use the transmission fluid I use for flushing? A: The very fine metal and clutch material debris from the transmission failure in the ATF causes failures with the hall effect speed sensors that are used to measure the flow rate. To avoid costly repairs, expensive filters, regular maintenance and problems caused by a partially restricted filter, the filter was not included. Q: What do I do if I need service on my machine? A: Call Kent-Moore Customer Service at 1-800-345-2233. The J 45096 has a one-year warranty. Q: Can I flush and flow engine oil coolers? A: The engine oil cooler flow rates, the appropriate adapters and an acceptable procedure are currently under development. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6343 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6344 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6347 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6348 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6349 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6350 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6351 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6352 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6353 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6354 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6355 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6356 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6357 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6358 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6359 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6360 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6361 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6362 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6363 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6364 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6365 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6366 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6367 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6368 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6369 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6370 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6371 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6372 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6373 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6374 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6375 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6376 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6377 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6378 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 6379 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Temperature Sensor/Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6384 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6385 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6386 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6387 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6388 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6389 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6390 Transmission Temperature Sensor/Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6391 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6392 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6393 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6394 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6395 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6396 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6397 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6398 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6399 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6400 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6401 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6402 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6403 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6404 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6405 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6406 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6407 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6408 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6409 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6410 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6411 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6412 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6413 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6414 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6415 Transmission Range Switch Assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Page 6416 Transmission Temperature Sensor/Switch: Description and Operation The Transmission Fluid Temperature (TFT) sensor is a thermistor (a device that changes resistance according to changes in temperature) used to indicate transmission fluid temperature. High sensor resistance produces high signal input voltage which corresponds to low fluid temperature. Low sensor resistance produces low signal input voltage which corresponds to high fluid temperature. The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following: ^ Torque Converter Clutch (TCC) apply and release schedules. ^ Hot mode determination. ^ Shift quality. The TFT sensor is part of the transmission range fluid pressure switch assembly and is attached to the control valve body within the transmission. A fault in the Transmission Fluid Temperature (TFT) sensor circuit will set a DTC 58. 59 or 79. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Automatic Transmission/Transaxle > Valve Body, A/T > Component Information > Technical Service Bulletins > A/T Control - DTC P0756 Diagnostic Tips Valve Body: Technical Service Bulletins A/T Control - DTC P0756 Diagnostic Tips INFORMATION Bulletin No.: 01-07-30-036H Date: January 29, 2009 Subject: Diagnostic Tips for Automatic Transmission DTC P0756, Second, Third, Fourth Gear Start Models: 2009 and Prior GM Passenger Cars and Light Duty Trucks 2009 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X with 4L60-E, 4L65-E or 4L70E Automatic Transmission (RPOs M30, M32 or M70) Supercede: This bulletin is being revised to add the 2009 model year and add details regarding spacer plates. Please discard Corporate Bulletin Number 01-07-30-036G (Section 07 - Transmission/Transaxle). Some dealership technicians may have difficulty diagnosing DTC P0756, 2-3 Shift Valve Performance on 4L60-E, 4L65-E or 4L70E automatic transmissions. As detailed in the Service Manual, when the PCM detects a 4-3-3-4 shift pattern, DTC P0756 will set. Some customers may also describe a condition of a second, third or fourth gear start that may have the same causes but has not set this DTC yet. Below are some tips when diagnosing this DTC: ^ This is a performance code. This means that a mechanical malfunction exists. ^ This code is not set by electrical issues such as a damaged wiring harness or poor electrical connections. Electrical problems would cause a DTC P0758, P0787 or P0788 to set. ^ The most likely cause is chips/debris plugging the filtered AFL oil at orifice # 29 on the top of the spacer plate (48). This is a very small hole and is easily plugged by a small amount of debris. It is important to remove the spacer plate and inspect orifice # 29 and the immediate area for the presence of chips/debris. Also, the transmission case passage directly above this orifice and the valve body passage directly below should be inspected and cleaned of any chips/debris. For 2003 and newer vehicles the spacer plate should be replaced. The service replacement spacer plate is a bonded style with gaskets and solenoid filter screens bonded to the spacer plate. These screens can help to prevent plugging of orifice # 29 caused by small debris or chips. ^ This code could be set if the 2-3 shift valve (368) were stuck or hung-up in its bore. Inspect the 2-3 shift valve (368) and the 2-3 shuttle valve (369) for free movement or damage and clean the valves, the bore and the valve body passages. ^ This code could be set by a 2-3 shift solenoid (367b) if it were cracked, broken or leaking. Refer to Shift Solenoid Leak Test in the appropriate Service Manual for the leak test procedure. Based on parts return findings, a damaged or leaking shift solenoid is the least likely cause of this condition. Simply replacing a shift solenoid will not correct this condition unless the solenoid has been found to be cracked, broken or leaking. It is important to also refer to the appropriate Service Manual or Service Information (SI) for further possible causes of this condition. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Clutch, M/T > Clutch Hydraulic System > Clutch Fluid > Component Information > Specifications > Capacity Specifications Clutch Fluid: Capacity Specifications Fill the clutch master cylinder to the "Full" or "MAX" mark on the reservoir. Do not overfill. Caution: Should accidental spillage occur, rinse the area thoroughly with water. Pay special attention to any electrical wires, parts, harnesses, rubber or painted surfaces. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Clutch, M/T > Clutch Hydraulic System > Clutch Fluid > Component Information > Specifications > Capacity Specifications > Page 6427 Clutch Fluid: Fluid Type Specifications Hydraulic Clutch Fluid ........................................................................................................................................ GM P/N 12345347 or DOT 3 Brake Fluid Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > Customer Interest: > 04-07-30-013B > Feb > 07 > Engine, A/T Shift/Driveability Concerns/MIL ON Continuously Variable Transmission/Transaxle: Customer Interest Engine, A/T - Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > Customer Interest: > 04-07-30-013B > Feb > 07 > Engine, A/T Shift/Driveability Concerns/MIL ON > Page 6436 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Continuously Variable Transmission/Transaxle: > 04-06-01-029E > Apr > 10 > Vehicle - Engine Crankcase and Subsystems Flushing Info. Continuously Variable Transmission/Transaxle: All Technical Service Bulletins Vehicle - Engine Crankcase and Subsystems Flushing Info. INFORMATION Bulletin No.: 04-06-01-029E Date: April 29, 2010 Subject: Unnecessary Flushing Services, Additive Recommendations and Proper Utilization of GM Simplified Maintenance Schedule to Enhance Customer Service Experience Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to update the model years and add information about the proper transmission flush procedure. Please discard Corporate Bulletin Number 04-06-01-029D (Section 06 - Engine/Propulsion System). An Overview of Proper Vehicle Service General Motors is aware that some companies are marketing tools and equipment to support a subsystem flushing procedures. These dedicated machines are in addition to many engine oil, cooling system, fuel system, A/C, transmission flush and steering system additives available to the consumer. GM Vehicles under normal usage do not require any additional procedures or additives beyond what is advised under the former Vehicle Maintenance Schedules or the current Simplified Maintenance Schedules. Do not confuse machines available from Kent-Moore/SPX that are designed to aid and accelerate the process of fluid changing with these flushing machines. Engine Crankcase Flushing General Motors Corporation does not endorse or recommend engine crankcase flushing for any of its gasoline engines. Analysis of some of the aftermarket materials used for crankcase flushing indicate incompatibility with GM engine components and the potential for damage to some engine seals and bearings. Damage to engine components resulting from crankcase flushing IS NOT COVERED under the terms of the New Vehicle Warranty. GM Authorized Service Information: Detailed, Descriptive, and Complete If a specific model vehicle or powertrain need is identified, GM will issue an Authorized Service Document containing a procedure and, if required, provide, make available, or require the specific use of a machine, tool or chemical to accomplish proper vehicle servicing. An example of this is fuel injector cleaning. Due to variation in fuel quality in different areas of the country, GM has recognized the need for fuel injector cleaning methods on some engines, though under normal circumstances, this service is not part of the maintenance requirements. GM has published several gasoline fuel injector cleaning bulletins that fully outline the methods to be used in conjunction with GM Part Numbered solutions to accomplish proper and safe cleaning of the fuel injectors with preventative maintenance suggestions to maintain optimum performance. You may refer to Corporate Bulletin Numbers 03-06-04-030 and 04-06-04-051 for additional information on this subject. Subsystem Flushing Flushing of A/C lines, radiators, transmission coolers, and power steering systems are recognized practices to be performed after catastrophic failures or extreme corrosion when encountered in radiators. For acceptable A/C flushing concerns, refer to Corporate Bulletin Number 01-01-38-006. This practice is NOT required or recommended for normal service operations. The use of external transmission fluid exchange or flush machines is NOT recommended for the automatic or manual transmission. Use of external machines to replace the fluid may affect the operation or durability of the transmission. Transmission fluid should only be replaced by draining and refilling following directions in SI. Refer to Automatic/Manual Transmission Fluid and Filter Replacement. Approved Transmission Flushing Tool (Transmission Cooler Only) The Automatic Transmission Oil Cooler Flush and Flow Test Tool is recommended for GM vehicles. Refer to Transmission Fluid Cooler Flushing and Flow Test in SI using the J 45096. Service Is Important to You and Your Customer General Motors takes great pride in offering our dealerships and customers high quality vehicles that require extremely low maintenance over the life of the vehicle. This low cost of ownership builds repeat sales and offers our customers measurable economy of operation against competing vehicles. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Continuously Variable Transmission/Transaxle: > 04-06-01-029E > Apr > 10 > Vehicle - Engine Crankcase and Subsystems Flushing Info. > Page 6442 Providing responsible services at the proper intervals will greatly aid your dealership with repeat business, and additional services when required. Most customers appreciate and gain trust in the dealership that informs and offers them just what they need for continued trouble-free operation. Examine your service department's practices and verify that all Service Consultants and Technicians focus on customer satisfaction, vehicle inspections, and other products at time of service. Use this opportunity to upgrade the services you provide to your customers. Here are a few suggestions: - Take the time required to align your dealership service practices with the new GM Simplified Maintenance Schedule. Use the new vehicle Owner's Manual Maintenance I and II schedules to create a "mirror image" in your advertising and dealer service pricing that is easily understandable to your customer. Taking advantage of this new service strategy may greatly increase your dealership service sales and customer retention while decreasing the frequency of visits and inconvenience to your customer. - Review your program to ensure that all vehicles coming in are evaluated for safety and wear items. Examine all vehicles for tire condition, signs of misalignment, brake wear, exterior lamp functionality, exhaust condition, A/C cooling performance, SRS or Air Bag MIL, along with Service Engine Soon or Check Engine indicators. If the Service Engine Soon or Check Engine MIL is illuminated, it is vital that you inform the customer of the concerns with ignoring the indicator and what the required repair would cost. In addition to the possibility of increased emissions and driveability concerns, many customers are unaware that lower gas mileage may also result, with additional cost to the customer. - Be complete in your service recommendations. Some sales opportunities are not being fully pursued nationally. Focus on overlooked but required maintenance that has real benefits to the customer. Many vehicles are equipped with cabin air filters. If these filters are used beyond replacement time, they may impede airflow decreasing A/C and heating performance. Make sure these filters are part of your recommended service. Note that some of our vehicles may not have been factory equipped but will accept the filters as an accessory. - Express the value in maintaining the finish quality of the customer's vehicle at the Maintenance I and II visits. More fully utilize the vehicle prep personnel you already have in place. In today's world, many people simply ignore the finish of their vehicle, at best infrequently using an automatic car wash for exterior cleaning. Offer vehicle detailing services in stages from just a wash and wax to a complete interior cleaning. When paired with the Simplified Maintenance visit, this will increase customer satisfaction. On return, the customer gets a visibly improved vehicle that will be a source of pride of ownership along with a vehicle that is now fully maintained. Also, reinforce the improved resale value of a completely maintained vehicle. - For customers who clean and maintain the appearance of their vehicles themselves encourage the use of GM Vehicle Care products. Many customers may have never used GM Car Wash/Wax Concentrate, GM Cleaner Wax or a longtime product, GM Glass Cleaner, which is a favorite of many customers who try it just once. If your dealership give samples of these products with new car purchases, customers may already be sold on the product but not willing to make a special trip to the dealership. Capitalize on sales at this time. Stock shelves right at the Service counter with these products and consider instituting compensation programs for Service Consultants who suggest these products. Many consumers faced with an intimidating wall full of car care products sold at local auto parts stores may find it comforting to purchase a fully tested product sold by GM that they know will not harm the finish of their vehicle. We suggest these competitively priced basic vehicle care products to emphasize: In USA: - #12378401 GM Vehicle Care Wash/Wax Concentrate 16 fl. oz. (0.473L) - #89021822 GM Vehicle Care Glass Cleaner Aerosol 18 oz. (510 g) - #12377966 GM Vehicle Care Cleaner Wax 16 fl. oz. (0.473L) - #1052929 GM Vehicle Care Chrome and Wire Wheel Cleaner 16 fl. oz. (0.473L) - #88861431 GM Vehicle Care Odor Eliminator 24 fl. oz. (0.710L) In Canada: - #10953203 GM Vehicle Care Wash & Wax Concentrate 473 mL - #992727 GM Glass Cleaner Aerosol 500 g - #10952905 GM Vehicle Care Liquid Cleaner/Wax 473 mL - #10953013 GM Vehicle Care Chrome Cleaner and Polish 454 mL - #10953202 GM Vehicle Care Wheel Brite 473 mL - #88901678 GM Vehicle Care Odor Eliminator 473 mL - Display signboards with the installed price for popular GM Accessories such as running boards and Tonneau Covers. Customers may not think to ask about these desirable items at the time of a service visit. - Finally, take advantage of the GM Goodwrench initiatives (Tire Program, Goodwrench Credit Card, etc. / Dealer Marketing Association (DMA) Promotions in Canada) to provide the customer with more reasons to identify your dealership as the best place to go for parts and service. Remember to utilize ALL of the service aspects you possess in your dealership to satisfy and provide value to your customer. Many businesses exist profitably as an oil change location, a vehicle repair facility, or a detailing shop alone. You already have the capabilities of all three and provide these services with the inherent trust of your customer, under the GM Mark of Excellence. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Continuously Variable Transmission/Transaxle: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON Continuously Variable Transmission/Transaxle: All Technical Service Bulletins Engine, A/T Shift/Driveability Concerns/MIL ON Bulletin No.: 04-07-30-013B Date: February 01, 2007 INFORMATION Subject: Automatic Transmission Shift, Engine Driveability Concerns or Service Engine Soon (SES) Light On as a Result of the Use of an Excessively/Over-Oiled Aftermarket, Reusable Air Filter Models: 2007 and Prior GM Cars and Light Duty Trucks 2007 and Prior Saturn Models 2003-2007 HUMMER H2 2006-2007 HUMMER H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to add models and model years. Please discard Corporate Bulletin Number 04-07-30-013A (Section 07 - Transmission/Transaxle). The use of an excessively/over-oiled aftermarket, reusable air filter may result in: Service Engine Soon (SES) light on Transmission shift concerns, slipping and damaged clutch(es) or band(s) Engine driveability concerns, poor acceleration from a stop, limited engine RPM range The oil that is used on these air filter elements may be transferred onto the Mass Air Flow (MAF) sensor causing contamination of the sensor. As a result, the Grams per Second (GPS) signal from the MAF may be low and any or all of the concerns listed above may occur. When servicing a vehicle with any of these concerns, be sure to check for the presence of an aftermarket reusable, excessively/over-oiled air filter. The MAF, GPS reading should be compared to a like vehicle with an OEM air box and filter under the same driving conditions to verify the concern. The use of an aftermarket reusable air filter DOES NOT void the vehicle's warranty. If an aftermarket reusable air filter is used, technicians should inspect the MAF sensor element and the air induction hose for contamination of oil prior to making warranty repairs. Transmission or engine driveability concerns (related to the MAF sensor being contaminated with oil) that are the result of the use of an aftermarket reusable, excessively/over-oiled air filter are not considered to be warrantable repair items. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Continuously Variable Transmission/Transaxle: > 04-07-30-013B > Feb > 07 > Engine, A/T - Shift/Driveability Concerns/MIL ON > Page 6447 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > All Other Service Bulletins for Continuously Variable Transmission/Transaxle: > 04-06-01-029E > Apr > 10 > Vehicle - Engine Crankcase and Subsystems Flushing Info. Continuously Variable Transmission/Transaxle: All Technical Service Bulletins Vehicle - Engine Crankcase and Subsystems Flushing Info. INFORMATION Bulletin No.: 04-06-01-029E Date: April 29, 2010 Subject: Unnecessary Flushing Services, Additive Recommendations and Proper Utilization of GM Simplified Maintenance Schedule to Enhance Customer Service Experience Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to update the model years and add information about the proper transmission flush procedure. Please discard Corporate Bulletin Number 04-06-01-029D (Section 06 - Engine/Propulsion System). An Overview of Proper Vehicle Service General Motors is aware that some companies are marketing tools and equipment to support a subsystem flushing procedures. These dedicated machines are in addition to many engine oil, cooling system, fuel system, A/C, transmission flush and steering system additives available to the consumer. GM Vehicles under normal usage do not require any additional procedures or additives beyond what is advised under the former Vehicle Maintenance Schedules or the current Simplified Maintenance Schedules. Do not confuse machines available from Kent-Moore/SPX that are designed to aid and accelerate the process of fluid changing with these flushing machines. Engine Crankcase Flushing General Motors Corporation does not endorse or recommend engine crankcase flushing for any of its gasoline engines. Analysis of some of the aftermarket materials used for crankcase flushing indicate incompatibility with GM engine components and the potential for damage to some engine seals and bearings. Damage to engine components resulting from crankcase flushing IS NOT COVERED under the terms of the New Vehicle Warranty. GM Authorized Service Information: Detailed, Descriptive, and Complete If a specific model vehicle or powertrain need is identified, GM will issue an Authorized Service Document containing a procedure and, if required, provide, make available, or require the specific use of a machine, tool or chemical to accomplish proper vehicle servicing. An example of this is fuel injector cleaning. Due to variation in fuel quality in different areas of the country, GM has recognized the need for fuel injector cleaning methods on some engines, though under normal circumstances, this service is not part of the maintenance requirements. GM has published several gasoline fuel injector cleaning bulletins that fully outline the methods to be used in conjunction with GM Part Numbered solutions to accomplish proper and safe cleaning of the fuel injectors with preventative maintenance suggestions to maintain optimum performance. You may refer to Corporate Bulletin Numbers 03-06-04-030 and 04-06-04-051 for additional information on this subject. Subsystem Flushing Flushing of A/C lines, radiators, transmission coolers, and power steering systems are recognized practices to be performed after catastrophic failures or extreme corrosion when encountered in radiators. For acceptable A/C flushing concerns, refer to Corporate Bulletin Number 01-01-38-006. This practice is NOT required or recommended for normal service operations. The use of external transmission fluid exchange or flush machines is NOT recommended for the automatic or manual transmission. Use of external machines to replace the fluid may affect the operation or durability of the transmission. Transmission fluid should only be replaced by draining and refilling following directions in SI. Refer to Automatic/Manual Transmission Fluid and Filter Replacement. Approved Transmission Flushing Tool (Transmission Cooler Only) The Automatic Transmission Oil Cooler Flush and Flow Test Tool is recommended for GM vehicles. Refer to Transmission Fluid Cooler Flushing and Flow Test in SI using the J 45096. Service Is Important to You and Your Customer General Motors takes great pride in offering our dealerships and customers high quality vehicles that require extremely low maintenance over the life of the vehicle. This low cost of ownership builds repeat sales and offers our customers measurable economy of operation against competing vehicles. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Continuously Variable Transmission/Transaxle, CVT > Component Information > Technical Service Bulletins > All Other Service Bulletins for Continuously Variable Transmission/Transaxle: > 04-06-01-029E > Apr > 10 > Vehicle - Engine Crankcase and Subsystems Flushing Info. > Page 6453 Providing responsible services at the proper intervals will greatly aid your dealership with repeat business, and additional services when required. Most customers appreciate and gain trust in the dealership that informs and offers them just what they need for continued trouble-free operation. Examine your service department's practices and verify that all Service Consultants and Technicians focus on customer satisfaction, vehicle inspections, and other products at time of service. Use this opportunity to upgrade the services you provide to your customers. Here are a few suggestions: - Take the time required to align your dealership service practices with the new GM Simplified Maintenance Schedule. Use the new vehicle Owner's Manual Maintenance I and II schedules to create a "mirror image" in your advertising and dealer service pricing that is easily understandable to your customer. Taking advantage of this new service strategy may greatly increase your dealership service sales and customer retention while decreasing the frequency of visits and inconvenience to your customer. - Review your program to ensure that all vehicles coming in are evaluated for safety and wear items. Examine all vehicles for tire condition, signs of misalignment, brake wear, exterior lamp functionality, exhaust condition, A/C cooling performance, SRS or Air Bag MIL, along with Service Engine Soon or Check Engine indicators. If the Service Engine Soon or Check Engine MIL is illuminated, it is vital that you inform the customer of the concerns with ignoring the indicator and what the required repair would cost. In addition to the possibility of increased emissions and driveability concerns, many customers are unaware that lower gas mileage may also result, with additional cost to the customer. - Be complete in your service recommendations. Some sales opportunities are not being fully pursued nationally. Focus on overlooked but required maintenance that has real benefits to the customer. Many vehicles are equipped with cabin air filters. If these filters are used beyond replacement time, they may impede airflow decreasing A/C and heating performance. Make sure these filters are part of your recommended service. Note that some of our vehicles may not have been factory equipped but will accept the filters as an accessory. - Express the value in maintaining the finish quality of the customer's vehicle at the Maintenance I and II visits. More fully utilize the vehicle prep personnel you already have in place. In today's world, many people simply ignore the finish of their vehicle, at best infrequently using an automatic car wash for exterior cleaning. Offer vehicle detailing services in stages from just a wash and wax to a complete interior cleaning. When paired with the Simplified Maintenance visit, this will increase customer satisfaction. On return, the customer gets a visibly improved vehicle that will be a source of pride of ownership along with a vehicle that is now fully maintained. Also, reinforce the improved resale value of a completely maintained vehicle. - For customers who clean and maintain the appearance of their vehicles themselves encourage the use of GM Vehicle Care products. Many customers may have never used GM Car Wash/Wax Concentrate, GM Cleaner Wax or a longtime product, GM Glass Cleaner, which is a favorite of many customers who try it just once. If your dealership give samples of these products with new car purchases, customers may already be sold on the product but not willing to make a special trip to the dealership. Capitalize on sales at this time. Stock shelves right at the Service counter with these products and consider instituting compensation programs for Service Consultants who suggest these products. Many consumers faced with an intimidating wall full of car care products sold at local auto parts stores may find it comforting to purchase a fully tested product sold by GM that they know will not harm the finish of their vehicle. We suggest these competitively priced basic vehicle care products to emphasize: In USA: - #12378401 GM Vehicle Care Wash/Wax Concentrate 16 fl. oz. (0.473L) - #89021822 GM Vehicle Care Glass Cleaner Aerosol 18 oz. (510 g) - #12377966 GM Vehicle Care Cleaner Wax 16 fl. oz. (0.473L) - #1052929 GM Vehicle Care Chrome and Wire Wheel Cleaner 16 fl. oz. (0.473L) - #88861431 GM Vehicle Care Odor Eliminator 24 fl. oz. (0.710L) In Canada: - #10953203 GM Vehicle Care Wash & Wax Concentrate 473 mL - #992727 GM Glass Cleaner Aerosol 500 g - #10952905 GM Vehicle Care Liquid Cleaner/Wax 473 mL - #10953013 GM Vehicle Care Chrome Cleaner and Polish 454 mL - #10953202 GM Vehicle Care Wheel Brite 473 mL - #88901678 GM Vehicle Care Odor Eliminator 473 mL - Display signboards with the installed price for popular GM Accessories such as running boards and Tonneau Covers. Customers may not think to ask about these desirable items at the time of a service visit. - Finally, take advantage of the GM Goodwrench initiatives (Tire Program, Goodwrench Credit Card, etc. / Dealer Marketing Association (DMA) Promotions in Canada) to provide the customer with more reasons to identify your dealership as the best place to go for parts and service. Remember to utilize ALL of the service aspects you possess in your dealership to satisfy and provide value to your customer. Many businesses exist profitably as an oil change location, a vehicle repair facility, or a detailing shop alone. You already have the capabilities of all three and provide these services with the inherent trust of your customer, under the GM Mark of Excellence. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Carrier > Component Information > Adjustments > Differential Side Bearing Preload Differential Carrier: Adjustments Differential Side Bearing Preload Fig. 11 Service Shim Thickness Chart. DIFFERENTIAL SIDE BEARING PRELOAD ADJUSTMENTS On these models, side bearing preload should be set before pinion is installed. If pinion is installed, remove ring gear. 1. Ensure bearing bores in housing and bearing caps are clean and free from burrs. 2. Measure production shims or service spacer and shim packs removed during disassembly to determine approximate thickness of shims needed for installation. Do not reuse cast iron production shims as they may break during installation. If service spacers and shims were previously installed, they can be reused. 3. In addition to .170 inch service spacers for each side, refer to chart, Fig. 11, and select service shim thickness required based on measurements made in step 2. 4. Place outer races over side bearings, mount differential assembly in housing and insert service spacer between each bearing race and housing with chamfered edge against housing. 5. Install left bearing cap to retain case assembly and tighten bolts hand tight so that case can be moved while checking adjustments. A bearing cap bolt can be installed in lower right bearing cap hole to prevent case from dropping while performing shim adjustments. 6. Select one or two shims totaling thickness calculated in step 3 and insert shims between right bearing cap and service spacer. 7. Insert progressively larger feeler gauges between shim and service spacer until noticeable increase in drag can be felt, pushing gauge down until it contacts housing bore to obtain proper reading. Rotate case while inserting gauges to ensure even readings. 8. The gauge used just before additional drag is felt is correct thickness to obtain "zero preload. By starting with a thin gauge a sense of feel can be obtained for the original light drag caused by the weight of the case, allowing the drag caused by the beginning of preload to be recognized. It will be necessary to work case in and out and to the left in order to insert feeler gauges. 9. When the proper gauge thickness has been determined to obtain zero preload, remove bearing cap, case assembly service spacers and shim pack. 10. Select two service shims of approximate equal thickness whose total thickness is equal to the thickness of the shims installed in step 6 plus the thickness of the feeler gauge used to obtain zero preload. 11. Shims selected during this procedure allow differential assembly to be installed at zero preload, the equivalent of a "slip-fit in case, during backlash adjustment. Final preload is not added until backlash has been adjusted. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Carrier > Component Information > Adjustments > Differential Side Bearing Preload > Page 6459 Differential Carrier: Adjustments Pinion Depth Adjustment Fig. 12 Pinion Gauge Plate Installation. Fig. 13 Pinion Depth Check. PINION DEPTH ADJUSTMENT 1. Install pinion bearing races in housing using a suitable driver. 2. Lubricate pinion bearings and install bearings in races. 3. Mount depth gauging jig in housing, Fig. 12, noting the following: a. Assemble gauge plate onto preload stud. b. Hold pinion bearings in position, insert stud through rear bearing and pilot and front bearing and pilot, then install retaining nut and tighten nut until snug. c. Rotate tool to ensure bearings are properly seated. d. Hold preload stud and tighten nut until 20 inch lbs. of torque is required to rotate stud. To prevent damage to bearing, tighten nut in small increments, checking rotating torque after each adjustment. e. Mount side bearing discs on arbor, using step for disc that corresponds to base of housing. f. Mount arbor and plunger assembly in housing, ensuring side bearing discs are properly seated, install bearing caps and tighten cap bolts to prevent bearing discs from moving, Fig. 13. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Carrier > Component Information > Adjustments > Differential Side Bearing Preload > Page 6460 4. Mount dial indicator on arbor stud with indicator contact button bearing against top of arbor plunger. 5. Preload indicator 3/4 revolution and secure to arbor mounting stud in this position. 6. Place arbor plunger on gauge plate, rotating plate as needed so that plunger rests directly on button corresponding to ring gear size. 7. Slowly rock plunger rod back and forth across button while observing dial indicator. 8. At point on button where indicator registers greatest deflection, zero dial indicator. Perform above two steps several times to ensure correct setting. 9. Once verified zero reading is obtained, swing plunger aside until it is clear of gauge plate button and record dial indicator reading. Indicator will now read required pinion depth shim thickness for a nominal pinion. 10. Inspect rear face of drive pinion to be installed for a pinion code number. This number indicates in thousandths of an inch necessary modification of pinion shim thickness obtained in step 9. 11. Select pinion depth adjusting shim as follows: a. If pinion is stamped with a plus (+) number, add that number of thousandths to dimension obtained in step 9. b. If pinion is stamped with a minus (−) number, subtract that many thousandths from dimension obtained in step 9. c. If pinion is not stamped with plus or minus number, dimension obtained in step 9 is correct shim thickness. 12. Remove gauging tools and pinion bearings from housing, noting installation position of bearings. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Locations LH Rear Frame Rail (Without Automatic Level Control) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Service and Repair > Disassemble and Disassemble Differential Axle Housing: Service and Repair Disassemble and Disassemble Fig. 3 Exploded View Of Rear Axle Assembly (Part 1 Of 2). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Service and Repair > Disassemble and Disassemble > Page 6466 Fig. 3 Exploded View Of Rear Axle Assembly (Part 2 Of 2). DISASSEMBLE 1. Raise and support rear of vehicle, then loosen axle housing cover bolts and allow lubricant to drain into suitable container, Fig. 3 . 2. Remove axle housing cover, then proceed as follows: a. Wipe excess lubricant from inside axle housing, then visually inspect parts for wear and/or damage. b. Rotate gears and check for roughness, indicating damaged bearings or gears. c. Install dial indicator on axle housing cover flange, then check and record ring gear to drive pinion backlash. 3. Remove rear axles and propeller shaft. Refer to appropriate chassis chapter for procedures. 4. If not previously marked, scribe reference marks on differential bearing caps to be used during reassembly, then loosen bearing cap bolts. 5. Using suitable tool, pry differential case, bearing races and shims out of housing until loose in the bearing caps. Remove bearing races, then the differential assembly. Mark side cups and shims for reference during reassembly. Fig. 15 Ring Gear & Pinion Backlash Check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Service and Repair > Disassemble and Disassemble > Page 6467 Fig. 7 Front Hub & Wheel Bearing Assembly. ASSEMBLE 1. Ensure pinion depth and bearing preload are properly adjusted, as described under Adjustments. See: Pinion Gear/Adjustments 2. Install differential case assembly and selected side bearing shims as described under Adjustments. See: Pinion Gear/Adjustments 3. Install bearing caps in proper position and torque cap bolts to 55 ft. lbs. 4. Rotate assembly to ensure bearings are properly seated. 5. Mount dial indicator on housing with plunger bearing against tooth on ring gear, Fig. 15. Use small contact button on indicator plunger so that contact can be made at heel end of tooth and position dial indicator with plunger inline with gear rotation and perpendicular to gear tooth. 6. Hold pinion stationary and rock ring gear back and forth while reading backlash on indicator. 7. Check backlash at three evenly spaced positions around ring gear and record readings. If backlash varies by more than 0.002 inch at any position, check ring gear installation and runout, and correct as needed. 8. If backlash is not within specifications, remove differential case assembly and bearing shims keeping shims in order. 9. Backlash is adjusted by increasing thickness of one shim while decreasing thickness of opposite side shim by the same amount in order to maintain proper side bearing preload. Select shims to adjust backlash as follows: a. If backlash is excessive, increase thickness of shim on gear tooth side and decrease thickness of shim on opposite side by the same amount. b. If backlash is less than specified, decrease thickness of shim on gear tooth side while increasing thickness of opposite shim by the same amount. Each 0.002 inch change in shim thickness alters backlash by 0.001 inch. 10. Reinstall differential assembly, shims and bearing caps, torque bearing cap bolts to 55 ft. lbs., then recheck backlash and adjust as needed. 11. If side bearing preload was set to zero during side bearing preload adjustment, proceed as follows: a. Remove both bearing caps and shim packs, keeping shim packs in respective left or right positions. b. Select left side differential preload shim from specifications chart and insert shim between left bearing race and spacer, then install left bearing cap with bolts hand tight. c. Select right side differential preload shim from specifications chart and insert shim between right bearing race and spacer using a soft faced hammer. d. Install right bearing cap and torque all cap bolts to 55 ft. lbs. 12. Ensure ring gear teeth are clean and free from oil, then coat both drive and coast side of each tooth with marking compound. 13. Apply braking force to load ring gear, then rotate driveshaft yoke with wrench so that ring gear rotates one full revolution in each direction. Test made without loading gears will not yield satisfactory pattern, excessive rotating of gears is not recommended. 14. Compare gear tooth pattern with Fig. 16, and correct assembly adjustments as needed. 15. When proper gear tooth contact pattern has been obtained, clean marking compound from gears. 16. Install axles and driveshaft. Refer to Drive/Propeller Shafts, Bearings and Joints for procedures. See: Drive/Propeller Shafts, Bearings and Joints/Drive/Propeller Shaft/Service and Repair 17. Install rear cover using RTV or new gasket and torque cover bolts to 20 ft. lbs., then fill rear axle with appropriate lubricant. 18. On models equipped with limited slip differential, add additive No. 1050428 or equivalent to rear axle lubricant. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Service and Repair > Disassemble and Disassemble > Page 6468 Differential Axle Housing: Service and Repair Cleaning & Inspection CLEANING AND INSPECTION 1. Clean components in solvent and blow dry with compressed air, noting the following: a. Do not use brush when cleaning bearings. b. Do not spin dry bearings, as bearings will be damaged. c. Lightly lubricate components after cleaning to retard corrosion. d. Keep all components in order to ensure proper assembly. 2. Inspect gears for cracks, chipped teeth, wear and scoring, and damaged bearing or mounting surfaces. Replace gears that are damaged or excessively worn. NOTE: Ring gear and pinion must be replaced as an assembly. 3. Inspect differential case for cracks, damage, worn side gear bores and scored bearing surfaces and replace as needed. 4. Inspect housing for scored bearing mount surfaces, cracks and distortion, and replace as needed. 5. Inspect bearing rollers and races for pitting, scoring, overheating and damage. 6. Mate bearing with race and check operation. 7. Replace any bearing that is damaged, excessively worn or that fails to operate smoothly. 8. Mount differential case along with side bearings and ring gear in housing, and check runout with side bearings adjusted for zero preload and a dial indicator positioned against machined edge of ring gear. 9. If runout exceeds 0.003 inch, and gear cannot be positioned to eliminate runout, ring gear and/or case should be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Service and Repair > Disassemble and Disassemble > Page 6469 Differential Axle Housing: Service and Repair Overhaul Standard Differential Fig. 3 Exploded View Of Rear Axle Assembly (Part 1 Of 2). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Service and Repair > Disassemble and Disassemble > Page 6470 Fig. 3 Exploded View Of Rear Axle Assembly (Part 2 Of 2). 1. If side carrier bearings are to be replaced, remove bearings using a bearing puller. 2. Remove differential pinion shaft lock bolt and the pinion shaft, Fig. 3 . 3. Remove differential pinions and thrust washers, side gears and side gear thrust washers, noting installation position for assembly. Keep thrust washers with respective gears. 4. Remove ring gear bolts, then the ring gear, driving ring gear from case using drift and hammer. Ring gear bolts have left hand threads. Do not pry between ring gear and case, as mating surfaces will be damaged. 5. Inspect components as outlined in Cleaning & Inspection and replace as needed. See: Cleaning & Inspection 6. Install thrust washers on side gears and mount side gears in case. Lubricate all components with specified gear lubricant prior to assembly. 7. Position one differential pinion (less thrust washer) between side gears and rotate gears until pinion is directly opposite case loading opening. 8. Install other pinion with pinion shaft holes aligned, then rotate side gears and ensure pinions align with shaft openings in case. 9. When pinions are properly aligned, rotate pinions toward loading opening just enough to allow thrust washer installation and install washers. 10. Align pinions with shaft opening in case, insert pinion shaft through case, install new lock bolt. It is not necessary to torque lock bolt at this time. 11. Ensure ring gear and case mating surfaces are clean and free from burrs, mount gear on case, install two new retaining bolts at opposite sides of gear and alternately tighten bolts to draw gear on case. 12. Install remaining ring gear bolts hand tight and ensure gear is squarely seated on case. Always use new bolts of proper type when installing ring gear. Do not reuse old bolts. 13. Alternately torque ring gear bolts to 89 ft. lbs. 14. Press side bearings onto case. If old bearings are reused, ensure bearings are installed in their original position. Limited Slip Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Differential Axle Housing > Component Information > Service and Repair > Disassemble and Disassemble > Page 6471 Fig. 7 Cutaway View Of Auburn Type Limited Slip Differential. These models use an Auburn Type limited slip differential Fig. 7 which can not be serviced. 1. Remove case side bearings using tool No. J-22888 or equivalent. 2. Remove all but two opposite ring gear attaching bolts, then loosen the two remaining bolts. 3. Loosen ring gear by tapping on bolts, then remove ring gear from differential. 4. This limited slip rear axle case is not serviceable. If differential case is not satisfactory, replace complete assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Fluid - Differential > Component Information > Technical Service Bulletins > Drivetrain - Recommended Axle Lubricant Fluid - Differential: Technical Service Bulletins Drivetrain - Recommended Axle Lubricant File In Section: 0 - General Information Bulletin No.: 76-02-02A Date: October, 1998 INFORMATION Subject: Recommended Axle Lubricant Models: 1999 and Prior Rear Wheel Drive Passenger Cars, Light and Medium Duty Trucks, and Four Wheel Drive Vehicles This bulletin is being revised to add the 1998 and 1999 Model Years and add Vehicle Line and Recommended Axle Lubricant Information. Please discard Corporate Bulletin Number 76-02-02 (Section 0 - General Information). The following tables provide the latest information on recommended axle lubricant. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Fluid - Differential > Component Information > Technical Service Bulletins > Drivetrain - Recommended Axle Lubricant > Page 6476 Parts Information Parts are currently available from GMSPO. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Fluid - Differential > Component Information > Technical Service Bulletins > Page 6477 Fluid - Differential: Specifications Fluid Type Standard Differential ^ SAE 80W-90 GL-5 gear lubricant Limited Slip Differential ^ Lubricant additive (GM P/N 1052358) and ^ SAE 80W-90 GL-5 gear lubricant Capacity Drain and Refill .................................................................................................................................... ................................................. 1.7 liters (3.5 pt) Additive ................................................................... .................................................................................................................... 118 milliliters (4 fl oz) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Bearing, Differential > Component Information > Adjustments > Differential Side Bearing Preload Pinion Bearing: Adjustments Differential Side Bearing Preload Fig. 11 Service Shim Thickness Chart. DIFFERENTIAL SIDE BEARING PRELOAD ADJUSTMENTS On these models, side bearing preload should be set before pinion is installed. If pinion is installed, remove ring gear. 1. Ensure bearing bores in housing and bearing caps are clean and free from burrs. 2. Measure production shims or service spacer and shim packs removed during disassembly to determine approximate thickness of shims needed for installation. Do not reuse cast iron production shims as they may break during installation. If service spacers and shims were previously installed, they can be reused. 3. In addition to .170 inch service spacers for each side, refer to chart, Fig. 11, and select service shim thickness required based on measurements made in step 2. 4. Place outer races over side bearings, mount differential assembly in housing and insert service spacer between each bearing race and housing with chamfered edge against housing. 5. Install left bearing cap to retain case assembly and tighten bolts hand tight so that case can be moved while checking adjustments. A bearing cap bolt can be installed in lower right bearing cap hole to prevent case from dropping while performing shim adjustments. 6. Select one or two shims totaling thickness calculated in step 3 and insert shims between right bearing cap and service spacer. 7. Insert progressively larger feeler gauges between shim and service spacer until noticeable increase in drag can be felt, pushing gauge down until it contacts housing bore to obtain proper reading. Rotate case while inserting gauges to ensure even readings. 8. The gauge used just before additional drag is felt is correct thickness to obtain "zero preload. By starting with a thin gauge a sense of feel can be obtained for the original light drag caused by the weight of the case, allowing the drag caused by the beginning of preload to be recognized. It will be necessary to work case in and out and to the left in order to insert feeler gauges. 9. When the proper gauge thickness has been determined to obtain zero preload, remove bearing cap, case assembly service spacers and shim pack. 10. Select two service shims of approximate equal thickness whose total thickness is equal to the thickness of the shims installed in step 6 plus the thickness of the feeler gauge used to obtain zero preload. 11. Shims selected during this procedure allow differential assembly to be installed at zero preload, the equivalent of a "slip-fit in case, during backlash adjustment. Final preload is not added until backlash has been adjusted. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Bearing, Differential > Component Information > Adjustments > Differential Side Bearing Preload > Page 6482 Pinion Bearing: Adjustments Pinion Depth Adjustment Fig. 12 Pinion Gauge Plate Installation. Fig. 13 Pinion Depth Check. PINION DEPTH ADJUSTMENT 1. Install pinion bearing races in housing using a suitable driver. 2. Lubricate pinion bearings and install bearings in races. 3. Mount depth gauging jig in housing, Fig. 12, noting the following: a. Assemble gauge plate onto preload stud. b. Hold pinion bearings in position, insert stud through rear bearing and pilot and front bearing and pilot, then install retaining nut and tighten nut until snug. c. Rotate tool to ensure bearings are properly seated. d. Hold preload stud and tighten nut until 20 inch lbs. of torque is required to rotate stud. To prevent damage to bearing, tighten nut in small increments, checking rotating torque after each adjustment. e. Mount side bearing discs on arbor, using step for disc that corresponds to base of housing. f. Mount arbor and plunger assembly in housing, ensuring side bearing discs are properly seated, install bearing caps and tighten cap bolts to prevent bearing discs from moving, Fig. 13. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Bearing, Differential > Component Information > Adjustments > Differential Side Bearing Preload > Page 6483 4. Mount dial indicator on arbor stud with indicator contact button bearing against top of arbor plunger. 5. Preload indicator 3/4 revolution and secure to arbor mounting stud in this position. 6. Place arbor plunger on gauge plate, rotating plate as needed so that plunger rests directly on button corresponding to ring gear size. 7. Slowly rock plunger rod back and forth across button while observing dial indicator. 8. At point on button where indicator registers greatest deflection, zero dial indicator. Perform above two steps several times to ensure correct setting. 9. Once verified zero reading is obtained, swing plunger aside until it is clear of gauge plate button and record dial indicator reading. Indicator will now read required pinion depth shim thickness for a nominal pinion. 10. Inspect rear face of drive pinion to be installed for a pinion code number. This number indicates in thousandths of an inch necessary modification of pinion shim thickness obtained in step 9. 11. Select pinion depth adjusting shim as follows: a. If pinion is stamped with a plus (+) number, add that number of thousandths to dimension obtained in step 9. b. If pinion is stamped with a minus (−) number, subtract that many thousandths from dimension obtained in step 9. c. If pinion is not stamped with plus or minus number, dimension obtained in step 9 is correct shim thickness. 12. Remove gauging tools and pinion bearings from housing, noting installation position of bearings. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Gear, Differential > Component Information > Adjustments > Differential Side Bearing Preload Pinion Gear: Adjustments Differential Side Bearing Preload Fig. 11 Service Shim Thickness Chart. DIFFERENTIAL SIDE BEARING PRELOAD ADJUSTMENTS On these models, side bearing preload should be set before pinion is installed. If pinion is installed, remove ring gear. 1. Ensure bearing bores in housing and bearing caps are clean and free from burrs. 2. Measure production shims or service spacer and shim packs removed during disassembly to determine approximate thickness of shims needed for installation. Do not reuse cast iron production shims as they may break during installation. If service spacers and shims were previously installed, they can be reused. 3. In addition to .170 inch service spacers for each side, refer to chart, Fig. 11, and select service shim thickness required based on measurements made in step 2. 4. Place outer races over side bearings, mount differential assembly in housing and insert service spacer between each bearing race and housing with chamfered edge against housing. 5. Install left bearing cap to retain case assembly and tighten bolts hand tight so that case can be moved while checking adjustments. A bearing cap bolt can be installed in lower right bearing cap hole to prevent case from dropping while performing shim adjustments. 6. Select one or two shims totaling thickness calculated in step 3 and insert shims between right bearing cap and service spacer. 7. Insert progressively larger feeler gauges between shim and service spacer until noticeable increase in drag can be felt, pushing gauge down until it contacts housing bore to obtain proper reading. Rotate case while inserting gauges to ensure even readings. 8. The gauge used just before additional drag is felt is correct thickness to obtain "zero preload. By starting with a thin gauge a sense of feel can be obtained for the original light drag caused by the weight of the case, allowing the drag caused by the beginning of preload to be recognized. It will be necessary to work case in and out and to the left in order to insert feeler gauges. 9. When the proper gauge thickness has been determined to obtain zero preload, remove bearing cap, case assembly service spacers and shim pack. 10. Select two service shims of approximate equal thickness whose total thickness is equal to the thickness of the shims installed in step 6 plus the thickness of the feeler gauge used to obtain zero preload. 11. Shims selected during this procedure allow differential assembly to be installed at zero preload, the equivalent of a "slip-fit in case, during backlash adjustment. Final preload is not added until backlash has been adjusted. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Gear, Differential > Component Information > Adjustments > Differential Side Bearing Preload > Page 6488 Pinion Gear: Adjustments Pinion Depth Adjustment Fig. 12 Pinion Gauge Plate Installation. Fig. 13 Pinion Depth Check. PINION DEPTH ADJUSTMENT 1. Install pinion bearing races in housing using a suitable driver. 2. Lubricate pinion bearings and install bearings in races. 3. Mount depth gauging jig in housing, Fig. 12, noting the following: a. Assemble gauge plate onto preload stud. b. Hold pinion bearings in position, insert stud through rear bearing and pilot and front bearing and pilot, then install retaining nut and tighten nut until snug. c. Rotate tool to ensure bearings are properly seated. d. Hold preload stud and tighten nut until 20 inch lbs. of torque is required to rotate stud. To prevent damage to bearing, tighten nut in small increments, checking rotating torque after each adjustment. e. Mount side bearing discs on arbor, using step for disc that corresponds to base of housing. f. Mount arbor and plunger assembly in housing, ensuring side bearing discs are properly seated, install bearing caps and tighten cap bolts to prevent bearing discs from moving, Fig. 13. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Gear, Differential > Component Information > Adjustments > Differential Side Bearing Preload > Page 6489 4. Mount dial indicator on arbor stud with indicator contact button bearing against top of arbor plunger. 5. Preload indicator 3/4 revolution and secure to arbor mounting stud in this position. 6. Place arbor plunger on gauge plate, rotating plate as needed so that plunger rests directly on button corresponding to ring gear size. 7. Slowly rock plunger rod back and forth across button while observing dial indicator. 8. At point on button where indicator registers greatest deflection, zero dial indicator. Perform above two steps several times to ensure correct setting. 9. Once verified zero reading is obtained, swing plunger aside until it is clear of gauge plate button and record dial indicator reading. Indicator will now read required pinion depth shim thickness for a nominal pinion. 10. Inspect rear face of drive pinion to be installed for a pinion code number. This number indicates in thousandths of an inch necessary modification of pinion shim thickness obtained in step 9. 11. Select pinion depth adjusting shim as follows: a. If pinion is stamped with a plus (+) number, add that number of thousandths to dimension obtained in step 9. b. If pinion is stamped with a minus (−) number, subtract that many thousandths from dimension obtained in step 9. c. If pinion is not stamped with plus or minus number, dimension obtained in step 9 is correct shim thickness. 12. Remove gauging tools and pinion bearings from housing, noting installation position of bearings. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Gear, Differential > Component Information > Service and Repair > Removal and Installation Pinion Gear: Service and Repair Removal and Installation REMOVAL 1. Scribe reference mark between drive pinion and driveshaft yoke, then hold yoke with suitable tool and remove pinion nut and yoke. If yoke shows wear in the seal-to-flange contacting surface, the yoke should be replaced. 2. Install original pinion nut a few turns on pinion shaft, then using hammer and drift, tap pinion shaft out of pinion housing. Hold gear end of pinion shaft when removing to prevent it from falling from axle housing. 3. Remove and discard pinion nut and collapsible spacer. 4. If being replaced, remove front and rear bearing races from pinion housing using drift positioned in race slots and hammer. 5. If rear pinion bearing is being replaced, remove using arbor press and adapters. Measure and record thickness of shim which is found under rear bearing. INSTALLATION 1. Install selected shim onto pinion shaft, lubricate rear pinion bearing with specified axle lubricant, then press rear bearing onto pinion using suitable spacers. 2. Install new collapsible spacer onto pinion shaft, then insert pinion assembly into housing. 3. Lubricate front pinion bearing, install bearing into housing and tap bearing over pinion shaft with a drift while assistant holds pinion in place. Old pinion nut and a large washer can be used to seat front bearing on pinion, but care must be taken not to collapse spacer if this method is used. 4. Install new pinion seal in housing, coat seal lips with grease, then mount driveshaft yoke on pinion shaft, lightly tapping yoke until several pinion shaft threads protrude from yoke. 5. Coat rear of pinion washer with suitable sealer, then install washer and new pinion nut. 6. Hold driveshaft yoke with suitable tool, then alternately tighten pinion nut and rotate pinion until endplay is reduced to zero. 7. When endplay is reduced to zero, check pinion bearing preload using a torque wrench. 8. Continue tightening pinion nut in small increments until 35-40 inch lbs. of bearing preload is obtained with new bearings or 20-25 inch lbs. of bearing preload is obtained with used bearings, rotating pinion and checking preload after each adjustment. NOTE: Exceeding preload specification will compress collapsible spacer too far, requiring replacement of spacer. If preload specification is exceeded, spacer must be replaced and adjustment procedure must be repeated. Do not loosen pinion nut to reduce preload. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Gear, Differential > Component Information > Service and Repair > Removal and Installation > Page 6492 Pinion Gear: Service and Repair Assemble and Preload Fig. 15 Ring Gear & Pinion Backlash Check. Fig. 7 Front Hub & Wheel Bearing Assembly. ASSEMBLE 1. Ensure pinion depth and bearing preload are properly adjusted, as described under Adjustments. See: Adjustments 2. Install differential case assembly and selected side bearing shims as described under Adjustments. See: Adjustments 3. Install bearing caps in proper position and torque cap bolts to 55 ft. lbs. 4. Rotate assembly to ensure bearings are properly seated. 5. Mount dial indicator on housing with plunger bearing against tooth on ring gear, Fig. 15. Use small contact button on indicator plunger so that contact can be made at heel end of tooth and position dial indicator with plunger inline with gear rotation and perpendicular to gear tooth. 6. Hold pinion stationary and rock ring gear back and forth while reading backlash on indicator. 7. Check backlash at three evenly spaced positions around ring gear and record readings. If backlash varies by more than 0.002 inch at any position, check ring gear installation and runout, and correct as needed. 8. If backlash is not within specifications, remove differential case assembly and bearing shims keeping shims in order. 9. Backlash is adjusted by increasing thickness of one shim while decreasing thickness of opposite side shim by the same amount in order to maintain Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Differential Assembly > Pinion Gear, Differential > Component Information > Service and Repair > Removal and Installation > Page 6493 proper side bearing preload. Select shims to adjust backlash as follows: a. If backlash is excessive, increase thickness of shim on gear tooth side and decrease thickness of shim on opposite side by the same amount. b. If backlash is less than specified, decrease thickness of shim on gear tooth side while increasing thickness of opposite shim by the same amount. Each 0.002 inch change in shim thickness alters backlash by 0.001 inch. 10. Reinstall differential assembly, shims and bearing caps, torque bearing cap bolts to 55 ft. lbs., then recheck backlash and adjust as needed. 11. If side bearing preload was set to zero during side bearing preload adjustment, proceed as follows: a. Remove both bearing caps and shim packs, keeping shim packs in respective left or right positions. b. Select left side differential preload shim from specifications chart and insert shim between left bearing race and spacer, then install left bearing cap with bolts hand tight. c. Select right side differential preload shim from specifications chart and insert shim between right bearing race and spacer using a soft faced hammer. d. Install right bearing cap and torque all cap bolts to 55 ft. lbs. 12. Ensure ring gear teeth are clean and free from oil, then coat both drive and coast side of each tooth with marking compound. 13. Apply braking force to load ring gear, then rotate driveshaft yoke with wrench so that ring gear rotates one full revolution in each direction. Test made without loading gears will not yield satisfactory pattern, excessive rotating of gears is not recommended. 14. Compare gear tooth pattern with Fig. 16, and correct assembly adjustments as needed. 15. When proper gear tooth contact pattern has been obtained, clean marking compound from gears. 16. Install axles and driveshaft. Refer to Drive/Propeller Shafts, Bearings and Joints for procedures. See: Drive/Propeller Shafts, Bearings and Joints/Drive/Propeller Shaft/Service and Repair 17. Install rear cover using RTV or new gasket and torque cover bolts to 20 ft. lbs., then fill rear axle with appropriate lubricant. 18. On models equipped with limited slip differential, add additive No. 1050428 or equivalent to rear axle lubricant. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Drive Axles, Bearings and Joints > Axle Shaft Assembly > Component Information > Service and Repair Axle Shaft Assembly: Service and Repair REAR AXLE SHAFT Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Drive Axles, Bearings and Joints > Axle Shaft Assembly > Component Information > Service and Repair > Page 6498 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Drive Axles, Bearings and Joints > Axle Shaft Assembly > Component Information > Service and Repair > Page 6499 Remove 1. Raise and suitably support vehicle. 2. Rear tire and wheels. 3. Rear brake drums, on vehicles equipped with rear drum brake systems. 4. Rotor and rear parking brake shoe lining, on vehicles equipped with rear disc brake systems. 5. Housing cover. 6. Bolt/screw (5) from case (7). 7. Pinion gear shaft (6) from case (7). 8. Shaft lock (38). ^ Access by pushing the flanged end of the shaft (39) into housing (37). 9. Axle shaft (39) from housing (37), being careful not to damage seal (34) or sensor (49) and sensor ring. ^ Hold a shop towel under axle shaft (39) to prevent axle lubricant from contaminating brake shoes and linings. Install 1. Shaft (39) into place taking care that splines on the end of shaft (39) do not damage seal (34) and that they engage with the splines of the side gear Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Drive Axles, Bearings and Joints > Axle Shaft Assembly > Component Information > Service and Repair > Page 6500 (10). ^ The 30-spline, 8 1/2-inch ring gear rear axle shaft is not interchangeable with any pre-1989 shaft. 2. Shaft lock (38). ^ Push axle shaft (39) outward so that shaft lock (38) seats in counterbore of side gear (10). 3. Pinion gear shaft (6) through case (7), thrust washers (11) and pinion gears (12), align the hole in shaft (6) with the shaft lock bolt/screw hole. 4. Bolt/screw (5). ^ Coat threads with Locktite 242 (GM P/N 12345382) or equivalent. Tighten Tighten bolt/screw (5) to 36 Nm (27 lb. ft.). 5 Housing cover. 6. rear brake drum. 7 Rotor and rear parking brake shoe and linings, if removed. 8 Rear tire and wheels. 9 Lower vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Drive Axles, Bearings and Joints > Wheel Bearing > Component Information > Adjustments Wheel Bearing: Adjustments FRONT WHEEL BEARINGS ADJUSTMENT Fig. 2 Front Wheel Bearing Adjustment 1. While rotating wheel forward, torque spindle nut to 12 ft. lbs., Fig. 2. 2. Back off nut until just loose then hand tighten nut and back it off again until either hole in spindle lines up with hole in nut. Do not back off nut more than 1/2 flat. 3. Install new cotter pin. With wheel bearing properly adjusted, there will be .001-.005 inch end play. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Drive Axles, Bearings and Joints > Wheel Bearing > Component Information > Adjustments > Page 6504 Wheel Bearing: Service and Repair FRONT WHEEL BEARINGS Fig. 3 Hub & Wheel Bearing Replacement 1. Raise car and remove front wheels. 2. On models equipped with anti-lock brake systems, remove right and left wheel speed sensors as follows: a. Under vehicle hood, disconnect speed sensor electrical harness. b. Raise and support vehicle, then remove speed sensor harness bracket attaching bolt. c. Remove speed sensor to steering knuckle attaching bolt, then remove speed sensor and bracket assembly and position aside. d. Reverse procedure to install. Install wheel speed sensors by hand. Do not hammer sensors into position, as damage may result. 3. On all models, remove bolts holding brake caliper to its mounting and insert a fabricated block (11/16 x 1 1/16 x 2 inches in length) between brake pads as caliper is being removed. Once removed, caliper can be wired or secured in some manner away from disc. 4. Remove spindle nut and hub and disc assembly. Grease retainer and inner wheel bearing can now be removed, Fig. 3. 5. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Drive/Propeller Shafts, Bearings and Joints > Drive/Propeller Shaft > Component Information > Service and Repair Drive/Propeller Shaft: Service and Repair 1. Raise and support vehicle. 2. Mark position of shaft in relation to pinion flange for reassembly. 3. Remove straps securing universal joint to pinion flange, then disconnect shaft from flange. Tape bearing cups to universal joint to prevent loss of needle bearings. 4. Slide yoke out of transmission and remove propeller shaft. Insert suitable plug in transmission to prevent fluid loss. 5. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6519 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6520 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6521 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6527 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6528 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6529 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 6530 Shift Indicator: Description and Operation DESCRIPTION This lamp is used on most models equipped with manual transmission. OPERATION The Upshift lamp is illuminated to inform the driver of ideal shift points, with improved fuel economy as the specific objective. When the light is illuminated, the transmission should be shifted to the next highest gear, if driving conditions permit such an action. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Lamps and Indicators - Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 6531 Shift Indicator: Service and Repair If upshift indicator is not working properly, perform the following test. 1. Disconnect ECM connector C1. 2. Place ignition switch in run. 3. Measure voltage at terminal A2 of ECM connector. 4. If battery voltage is present, further ECM diagnosis is necessary. 5. If battery voltage is not present, repair open circuit in brown/black wire, circuit 456. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Manual Transmission/Transaxle > Fluid - M/T > Component Information > Specifications Fluid - M/T: Specifications Fluid Type ........................................................................................................................................................ DEXRON-IIE or DEXRON-III auto. trans. Capacity Drain & Refill ........................................................................................................................................ .............................................. 4.7 liters (10.0 pt) Overhaul .................................................................. .......................................................................................................................... 10.6 liters (22.4 pt) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6542 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6543 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6546 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6547 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6548 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6549 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6550 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6551 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6552 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6553 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6554 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6555 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6556 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6557 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6558 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6559 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6560 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6561 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6562 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6563 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6564 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6565 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6566 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6567 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6568 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6569 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6570 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6571 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6572 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6573 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6574 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6575 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6576 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6577 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 6578 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Temperature Sensor/Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6583 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6584 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6585 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6586 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6587 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6588 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6589 Transmission Temperature Sensor/Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6590 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6591 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6592 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6593 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6594 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6595 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6596 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6597 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6598 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6599 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6600 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6601 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6602 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6603 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6604 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6605 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6606 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6607 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6608 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6609 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6610 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6611 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6612 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6613 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6614 Transmission Range Switch Assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Sensors and Switches - Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Page 6615 Transmission Temperature Sensor/Switch: Description and Operation The Transmission Fluid Temperature (TFT) sensor is a thermistor (a device that changes resistance according to changes in temperature) used to indicate transmission fluid temperature. High sensor resistance produces high signal input voltage which corresponds to low fluid temperature. Low sensor resistance produces low signal input voltage which corresponds to high fluid temperature. The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following: ^ Torque Converter Clutch (TCC) apply and release schedules. ^ Hot mode determination. ^ Shift quality. The TFT sensor is part of the transmission range fluid pressure switch assembly and is attached to the control valve body within the transmission. A fault in the Transmission Fluid Temperature (TFT) sensor circuit will set a DTC 58. 59 or 79. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates Torque Converter Clutch Solenoid: Technical Service Bulletins A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates File In Section: 7 - Transmission Bulletin No.: 47-71-41 Date: January, 1995 Subject: New 2-4 Band Assembly, 3-4 Clutch Friction and Steel Plates and Torque Clutch PWM Solenoid Models: 1995 Buick Roadmaster 1995 Cadillac Fleetwood 1995 Chevrolet Camaro, Caprice, Corvette 1995 Pontiac Firebird 1995 Chevrolet and GMC Truck C/K Models and M/L, G Vans 1994-95 Chevrolet and GMC Truck S/T Models 1994 Oldsmobile Bravada (1994 Models with RPO +CTF Package) Transmission Applications: 1995 Hydra-Matic 4L60-E (RPO M30) A new 2-4 Band Assembly was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The 2-4 Band friction material has changed appearance from a brown material to a gray/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 2-4 Band is burned/damaged due to its dark color. This dark color is normal. Before replacing the 2-4 Band inspect it for scoring, chunking or heavily worn friction material. Before Replacing the Reverse Input Housing and Drum Assembly inspect for scoring or signs of excessive heat. The 2-4 Band and/or Reverse Input Housing and Drum Assembly should be replaced ONLY if the above listed damage is found. Note: The new 2-4 Band Assembly will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new 3-4 clutch friction plate was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T Trucks. The 3-4 clutch plate friction material has changed appearance from a brown material to a green/black material. This change was made to enhance durability. When servicing a 1995 Hydra-Matic 4L60-E transmission, do NOT assume that the 3-4 clutch friction plates are burned/damaged due to their dark color. This dark color is normal. Before replacing the 3-4 clutch friction plates inspect for scoring, chunking or heavily worn friction material. Before replacing the 3-4 clutch steel plates inspect for scoring or signs of excessive heat. The 3-4 clutch friction plates and/or 3-4 clutch steel plates should be replaced ONLY if the above listed damage is found. Note: The new 3-4 friction plates will NOT service past model Hydra-Matic 4L60-E or 4L60 transmissions. A new Torque Converter Clutch PWM Solenoid was introduced at the start of production for the 1995 Model Year and 1994 Bravadas and S/T trucks. The new torque converter clutch PWM solenoid is used to control fluid acting on the converter clutch valve, which then controls TCC apply and release. The solenoid is attached to the control valve body assembly within the transmission. The TCC PWM solenoid is used to provide smooth engagement of the torque converter by operating on a negative duty cycle percent of "ON" time. It a fault is detected in the TCC PWM circuit, DTC 83 will set. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6623 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > A/T - 2-4 Band, TCC Solenoid, 3-4 Clutch Friction/Plates > Page 6624 Included is a Service Manual update for the 1-2 and 3-4 accumulator spring color chart. Replace these pages in your 1995 Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Actuators and Solenoids Transmission and Drivetrain > Actuators and Solenoids - A/T > Torque Converter Clutch Solenoid, A/T > Component Information > Technical Service Bulletins > Page 6625 Torque Converter Clutch Solenoid: Service and Repair REPLACE 1. Raise and support vehicle. 2. Disconnect heated oxygen sensor. 3. Remove catalytic converter to muffler attaching bolts and nuts. 4. Remove catalytic converter hanger to catalytic converter bolts. 5. Remove righthand side dampener assembly. 6. Remove nuts holding exhaust pipe to exhaust manifold. 7. Remove converter and pipe assembly from vehicle. 8. Remove oil pan and oil filter assembly. 9. Disconnect external wiring harness from transmission pass through connector. 10. Remove accumulator cover attaching bolts. 11. Remove 1-2 accumulator cover, piston and spring. 12. Disconnect electrical connectors. 13. Remove pressure control solenoid retainer bolt, then the retainer and solenoid. 14. Remove TCC solenoid retaining bolts. 15. Remove pass-through electrical connector from transmission case by positioning the small end of power piston seal protector and diaphragm retainer installer tool No. J-28458 or equivalent, over the top of the connector, then twist tool to release the four tabs while at the same time pulling the harness through the case. 16. Remove TCC solenoid with wiring harness from transmission case. 17. Reverse procedure to install, noting the following: a. Tighten TCC solenoid retaining bolt to specification. b. Tighten pressure control solenoid retaining bolt to specification. c. When installing 1-2 accumulator piston to accumulator cover, the piston legs must face towards the case. d. Tighten accumulator attaching bolts to specification Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6636 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6637 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6638 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6644 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6645 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 6646 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 6647 Shift Indicator: Description and Operation DESCRIPTION This lamp is used on most models equipped with manual transmission. OPERATION The Upshift lamp is illuminated to inform the driver of ideal shift points, with improved fuel economy as the specific objective. When the light is illuminated, the transmission should be shifted to the next highest gear, if driving conditions permit such an action. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Lamps and Indicators Transmission and Drivetrain > Lamps and Indicators - A/T > Shift Indicator > Component Information > Technical Service Bulletins > Page 6648 Shift Indicator: Service and Repair If upshift indicator is not working properly, perform the following test. 1. Disconnect ECM connector C1. 2. Place ignition switch in run. 3. Measure voltage at terminal A2 of ECM connector. 4. If battery voltage is present, further ECM diagnosis is necessary. 5. If battery voltage is not present, repair open circuit in brown/black wire, circuit 456. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations Transmission Position Switch/Sensor: Component Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6655 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Locations > Component Locations > Page 6656 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Position Switch/Sensor: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6659 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6660 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6661 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6662 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6663 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6664 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6665 Transmission Position Switch/Sensor: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6666 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6667 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6668 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6669 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6670 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6671 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6672 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6673 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6674 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6675 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6676 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6677 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6678 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6679 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6680 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6681 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6682 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6683 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6684 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6685 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6686 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6687 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6688 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6689 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6690 Park/Neutral Position Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Position Switch/Sensor, A/T > Component Information > Diagrams > Page 6691 Transmission Position Switch/Sensor: Description and Operation The Park/Neutral Position (PNP) switch indicates to the Powertrain Control Module (PCM) when the transmission is in park, neutral or drive. This information is used for the Torque Converter Clutch (TCC), Exhaust Gas Recirculation (EGR) and the Idle Air Control (IAC) valve operation. CAUTION: Vehicle should not be driven with park/neutral position switch disconnected, as idle quality will be affected and a possible false Diagnostic Trouble Code (DTC) 24 (Vehicle speed Sensor) may set. The PNP switch is part of the neutral/start and backup light switch assembly. Refer to CHART C-1A for PNP switch check. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions Transmission Temperature Sensor/Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6696 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6697 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6698 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6699 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6700 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6701 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6702 Transmission Temperature Sensor/Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6703 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6704 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6705 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6706 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6707 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6708 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6709 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6710 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6711 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6712 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6713 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6714 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6715 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6716 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6717 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6718 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6719 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6720 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6721 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6722 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6723 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6724 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6725 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6726 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Diagram Information and Instructions > Page 6727 Transmission Range Switch Assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Transmission and Drivetrain > Transmission Control Systems > Sensors and Switches Transmission and Drivetrain > Sensors and Switches - A/T > Transmission Temperature Sensor/Switch, A/T > Component Information > Diagrams > Page 6728 Transmission Temperature Sensor/Switch: Description and Operation The Transmission Fluid Temperature (TFT) sensor is a thermistor (a device that changes resistance according to changes in temperature) used to indicate transmission fluid temperature. High sensor resistance produces high signal input voltage which corresponds to low fluid temperature. Low sensor resistance produces low signal input voltage which corresponds to high fluid temperature. The Powertrain Control Module (PCM) uses the TFT sensor signal input to determine the following: ^ Torque Converter Clutch (TCC) apply and release schedules. ^ Hot mode determination. ^ Shift quality. The TFT sensor is part of the transmission range fluid pressure switch assembly and is attached to the control valve body within the transmission. A fault in the Transmission Fluid Temperature (TFT) sensor circuit will set a DTC 58. 59 or 79. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > ABS Light > Component Information > Description and Operation ABS Light: Description and Operation This lamp will be illuminated when the ignition switch is placed in the ON position. The lamp may be illuminated for as long as 30 seconds as a bulb and system check. If lamp remains illuminated or comes on while operating the vehicle, a problem in the anti-lock brake system is indicated. When lamp is illuminated, place ignition switch in OFF position, then restart engine. If lamp still remains illuminated, the anti-lock brake system should be serviced. The brake system will remain functional, but without the anti-lock function. After servicing the anti-lock brake system the lamp will automatically reset. On some models it may be necessary to operate vehicle at a speed over 18 mph to reset lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > ABS Main Relay > Component Information > Service and Repair ABS Main Relay: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Remove ABS modulator protective cover. 3. Remove relay from modulator. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Brake Fluid Pump > Component Information > Locations Brake Fluid Pump: Locations The pump motor located in the modulator circulates brake fluid back to the master cylinder circuit during anti-lock braking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Brake Fluid Pump > Component Information > Locations > Page 6740 Brake Fluid Pump: Description and Operation DESCRIPTION The pump motor located in the modulator circulates brake fluid back to the master cylinder circuit during anti-lock braking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Electronic Brake Control Module > Component Information > Locations Brake Pressure Modulator Valve (With Electronic Brake Control Module) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Electronic Brake Control Module > Component Information > Locations > Page 6744 Brake Pressure Modulator Valve (BPMV) (With Electronic Brake Control Module (EBCM)) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Electronic Brake Control Module > Component Information > Locations > Page 6745 Electronic Brake Control Module: Description and Operation DESCRIPTION The EBCM is a small control computer located under the trim panel on the lefthand side of the passenger compartment on wagon models, and on the lefthand side of the luggage compartment on sedan models. This computer monitors the speed of each wheel and the electrical status of the hydraulic modulator. The primary functions of EBCM are to detect wheel locking, control the brake function while in anti-lock mode and monitor system for correct electrical operation. The EBCM also controls the display of the ABS diagnostic trouble codes. If the EBCM detects a fault, it can disable the ABS system and activate the ABS warning lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Electronic Brake Control Module > Component Information > Locations > Page 6746 Electronic Brake Control Module: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Disconnect EBCM electrical connector. 3. Remove two EBCM to bracket attaching nuts, then the EBCM from the vehicle. 4. Reverse procedure to install, perform ABS system check as described in System Diagnosis. See: Testing and Inspection Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Locations > ABS Solenoid Valves Hydraulic Control Assembly - Antilock Brakes: Locations ABS Solenoid Valves The solenoid valves are located inside the hydraulic modulator are not serviceable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Locations > ABS Solenoid Valves > Page 6751 Hydraulic Control Assembly - Antilock Brakes: Locations Brake Pressure Modulator The hydraulic modulator (also known as Brake Pressure Modulator (BPM) or Pressure Modulator Valve (PMV)) is located on the front lefthand side of the engine compartment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Locations > ABS Solenoid Valves > Page 6752 Brake Pressure Modulator Valve (With Electronic Brake Control Module) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Locations > Page 6753 Hydraulic Control Assembly - Antilock Brakes: Diagrams Brake Pressure Modulator Valve (BPMV) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Locations > Page 6754 Brake Pressure Modulator Valve (BPMV) (With Electronic Brake Control Module (EBCM)) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Description and Operation > ABS Solenoid Valves Hydraulic Control Assembly - Antilock Brakes: Description and Operation ABS Solenoid Valves DESCRIPTION The solenoid valves are located inside the hydraulic modulator are not serviceable. The solenoid valves increase, decrease or maintain the brake fluid pressure to the wheel circuits. During anti-lock braking the valves are controlled by signals received by the EBCM/EBTCM. During normal braking, the valves are positioned in a pressure increase or open position. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Description and Operation > ABS Solenoid Valves > Page 6757 Hydraulic Control Assembly - Antilock Brakes: Description and Operation Hydraulic Modulator Valve DESCRIPTION The hydraulic modulator (also known as Brake Pressure Modulator (BPM) or Pressure Modulator Valve (PMV)) is located on the front lefthand side of the engine compartment, provides brake fluid modulation for each individual wheel circuit as required during anti-lock braking. During anti-lock braking, the modulator can maintain or reduce brake fluid pressure independent of the pressure generated in the master cylinder. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Hydraulic Control Assembly - Antilock Brakes > Component Information > Description and Operation > Page 6758 Hydraulic Control Assembly - Antilock Brakes: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Disconnect and remove air intake duct and resonator, then position upper coolant hose aside. 3. Disconnect canister purge line at canister and position aside. 4. Remove modulator valve cover attaching screw and cover. 5. Disconnect modulator valve electrical connector and ground wire. 6. Disconnect all hydraulic lines to modulator valve, then plug pipes to prevent loss of fluid and fluid contamination. Note location of pipes for installation reference. 7. Remove three modulator valve to bracket attaching nuts, then the modulator valve from vehicle. 8. Reverse procedure to install, then perform ABS system check as described in System Diagnosis. See: Testing and Inspection NOTE: Ensure brake hydraulic pipes are installed correctly. Pipes that are crossed during installation could cause wheel lock-up. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front Wheel Speed Sensor: Locations Wheel Speed Sensor Lead, Front LH Rear Engine Compartment LH Front Frame Rail RH Front Frame Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 6763 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 6764 Wheel Speed Sensor: Locations Wheel Speed Sensor, Rear LH Rear Frame Rail (Without Automatic Level Control) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 6765 Antilock Brake System Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Locations > Page 6766 Wheel Speed Sensor: Description and Operation DESCRIPTION These sensors transmit wheel speed information to the EBCM using a small amount of AC voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor Wheel Speed Sensor: Service and Repair Left Front Wheel Speed Sensor REPLACEMENT 1. Raise and support vehicle. 2. Disconnect wheel speed sensor harness connector and sensor assembly connector from clip. 3. Disconnect speed sensor connector from harness connector. 4. Remove sensor bracket attaching bolt from frame rail. 5. Disconnect wheel speed sensor assembly harness with grommets from brackets and combination valve brake pipe clip. Note position of grommets and harness for installation reference. 6. Remove speed sensor retaining bolt, then the speed sensor from steering knuckle. 7. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the knuckle and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor > Page 6769 Wheel Speed Sensor: Service and Repair Rear Axle Speed Sensor 1. Raise and support vehicle. 2. Unclip sensor assembly connector and differential sensor connector, then separate the connectors. 3. Disconnect speed sensor harness assembly wiring harness with gromments from sensor bracket. Note position of grommets and harness for installation reference. 4. Remove sensor attaching bolt, then the sensor from the vehicle. 5. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the axle housing and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Antilock Brakes / Traction Control Systems > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor > Page 6770 Wheel Speed Sensor: Service and Repair Right Front Wheel Speed Sensor REPLACEMENT 1. Disconnect forward lamp harness wheel speed sensor connector and wheel speed sensor assembly connector from clip. 2. Disconnect forward lamp harness connector from wheel speed sensor connector. 3. Raise and support vehicle. 4. Remove sensor bracket attaching bolt from frame rail. 5. Remove sensor assembly harness with grommets from brackets. Note position of grommets and harness for assembly reference. 6. Remove sensor retaining bolt, then the sensor from vehicle. 7. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the knuckle and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Bleeding > System Information > Service and Repair > With ABS System Brake Bleeding: Service and Repair With ABS System Manual Bleeding Fig. 210 Brake System Manual Bleed. NOTE: Pressure bleeding is recommended for all hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure. CAUTION: Brake fluid damages painted surfaces. Immediately clean any spilled fluid. 1. Remove vacuum reserve by pumping brakes several times with engine off. 2. Fill master cylinder reservoir with clean brake fluid. Check fluid level often during bleeding procedure; do not let reservoir fall below half full. 3. If necessary, bleed master cylinder as follows: a. Disconnect master cylinder forward brake line connection until fluid flows from reservoir. Reconnect and tighten brake line. b. Instruct an assistant to slowly depress brake pedal one time and hold. c. Crack open front brake line connection again, purging air from cylinder. d. Retighten connection and slowly release brake pedal. e. Wait 15 seconds, then repeat until all air is purged. f. Bleed the rearward (nearest the cowl) brake line connection by repeating preceding steps. 4. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 5. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleed Sequence. See: Wheel Bleed Sequence 6. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 210. Ensure end of tube is submerged in clean brake fluid. 7. Instruct an assistant to slowly depress brake pedal one time and hold. 8. Crack open bleeder valve, purging air from cylinder. Retighten bleeder screw and slowly release pedal. 9. Wait 15 seconds, then repeat preceding bleed steps. Repeat these steps until all air is bled from system. Pressure Bleeding Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6775 Fig. 210 Brake System Manual Bleed. Fig. 21 Installing Pressure Bleeder Adapter 1. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 2. Using a diaphragm type pressure bleeder, install suitable bleeder adapter to master cylinder, Fig. 211. 3. Charge bleeder ball to 20-25 psi. 4. Connect pressure bleeder line to adapter. 5. Open line valve on pressure bleeder, then depress bleed-off valve on adapter until a small amount of brake fluid is released. 6. Raise and support vehicle. 7. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. See: Wheel Bleed Sequence 8. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 210. Ensure end of tube is submerged in clean brake fluid. 9. Open bleeder valve 1/2 to 3/4 turn and allow fluid to flow into container until all air is purged from line. Wheel Bleed Sequence If manual bleeding, RR-LR-RF-LF; if pressure bleeding, bleed front brakes together and rear brakes together. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6776 Brake Bleeding: Service and Repair Without ABS System Manual Fig. 210 Brake System Manual Bleed. NOTE: Pressure bleeding is recommended for all hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure. Brake fluid damages painted surfaces. Immediately clean any spilled fluid. 1. Remove vacuum reserve by pumping brakes several times with engine off. 2. Fill master cylinder reservoir with clean brake fluid. Check fluid level often during bleeding procedure; do not let reservoir fall below half full. 3. If necessary, bleed master cylinder as follows: a. Disconnect master cylinder forward brake line connection until fluid flows from reservoir. Reconnect and tighten brake line. b. Instruct an assistant to slowly depress brake pedal one time and hold. c. Crack open front brake line connection again, purging air from cylinder. d. Retighten connection and slowly release brake pedal. e. Wait 15 seconds, then repeat until all air is purged. f. Bleed the rearward (nearest the cowl) brake line connection by repeating steps a through e. 4. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 5. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. 6. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 16. Ensure end of tube is submerged in clean brake fluid. 7. Instruct an assistant to slowly depress brake pedal one time and hold. 8. Crack open bleeder valve, purging air from cylinder. Retighten bleeder screw and slowly release pedal. 9. Wait 15 seconds, then repeat steps 7 and 8. Repeat these steps until all air is bled from system. Pressure Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6777 Fig. 21 Installing Pressure Bleeder Adapter Fig. 210 Brake System Manual Bleed. 1. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 2. Using a diaphragm type pressure bleeder, install suitable bleeder adapter to master cylinder, Fig. 17. 3. Charge bleeder ball to 20-25 psi. 4. Connect pressure bleeder line to adapter. 5. Open line valve on pressure bleeder, then depress bleed-off valve on adapter until a small amount of brake fluid is released. 6. Raise and support vehicle. 7. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. 8. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 16. Ensure end of tube is submerged in clean brake fluid. 9. Open bleeder valve 1/2 to 3/4 turn and allow fluid to flow into container until all air is purged from line. Front Disc Brakes NOTE: Pressure bleeding is recommended for all hydraulic disc brake systems. The disc brake hydraulic system can be bled manually or with pressure bleeding equipment. On vehicles with disc brakes the brake pedal will require more pumping and frequent checking of fluid level in master cylinder during bleeding operation. Never use brake fluid that has been drained from hydraulic system when bleeding the brakes. Be sure the disc brake pistons are returned to their normal positions and that the shoe and lining assemblies are properly seated. Before driving the vehicle, check brake operation to be sure that a firm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6778 pedal has been obtained. Rear Disc Brakes NOTE: Pressure bleeding is recommended for all hydraulic disc brake systems. The disc brake hydraulic system can be bled manually or with pressure bleeding equipment. On vehicles with disc brakes the brake pedal will require more pumping and frequent checking of fluid level in master cylinder during bleeding operation. Never use brake fluid that has been drained from hydraulic system when bleeding the brakes. Be sure the disc brake pistons are returned to their normal positions and that the shoe and lining assemblies are properly seated. Before driving the vehicle, check brake operation to be sure that a firm pedal has been obtained. Wheel Bleeding Sequence Rear wheel drive models: if manual bleeding, RR-LR-RF-LF; if pressure bleeding, bleed front brakes together and rear brakes together. Front wheel drive models: RR-LF-LR-RF Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions Brake Warning Indicator: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6783 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6784 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6785 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6786 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6787 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6788 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6789 Brake Warning Indicator: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6790 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6791 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6792 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6793 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6794 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6795 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6796 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6797 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6798 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6799 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6800 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6801 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6802 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6803 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6804 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6805 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6806 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6807 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6808 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6809 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6810 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6811 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6812 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6813 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 6814 Brake Warning System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Description and Operation > Brake Warning System Brake Warning Indicator: Description and Operation Brake Warning System DESCRIPTION The "Brake" warning indicator will be illuminated when a low brake fluid level in the master cylinder is sensed or when the Electronic Brake Control Module (EBCM) lights it in response to certain diagnostic trouble codes. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Description and Operation > Brake Warning System > Page 6817 Brake Warning Indicator: Description and Operation Circuit Operation Voltage is applied to the "BRAKE" Indicator from I/P Fuse #11 when the Ignition Switch is turned to "RUN," "BULB TEST" or "START." The "BRAKE" Indicator is controlled by any one of three switches: the Brake Pressure Switch, Ignition Switch or Park Brake Indicator Switch. When the Ignition Switch is turned to "BULB TEST" or "START," CKT 209 is grounded through the Ignition Switch to activate the "BRAKE" Indicator. When the Brake Pressure Switch is closed, CKT 209 is grounded through the contacts of the Brake Pressure Switch to activate the "BRAKE" Indicator. CKT 33 is grounded through the Park Brake Switch when the Park Brake is set, to activate the "BRAKE" Indicator. With the Daytime Running Lamps (DRL) Control Module grounded through CKT 33, the module provides ground to CKT 209, lighting the "BRAKE" Indicator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Description and Operation > Brake Warning System > Page 6818 Brake Warning Indicator: Description and Operation Brake Pressure Warning Lamp DESCRIPTION The warning lamp should illuminate when the ignition switch is in the start position, and turn off when the switch returns to run. If the brake lamp remains on after the ignition returns to run, check fluid level in master cylinder reservoir and inspect parking brake. If the warning lamp does not turn on during cranking, check for defective bulb or blown fuse. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Brake Warning Indicator: Initial Inspection and Diagnostic Overview Circuit Operation Voltage is applied to the "BRAKE" Indicator from I/P Fuse #11 when the Ignition Switch is turned to "RUN," "BULB TEST" or "START." The "BRAKE" Indicator is controlled by any one of three switches: the Brake Pressure Switch, Ignition Switch or Park Brake Indicator Switch. When the Ignition Switch is turned to "BULB TEST" or "START," CKT 209 is grounded through the Ignition Switch to activate the "BRAKE" Indicator. When the Brake Pressure Switch is closed, CKT 209 is grounded through the contacts of the Brake Pressure Switch to activate the "BRAKE" Indicator. CKT 33 is grounded through the Park Brake Switch when the Park Brake is set, to activate the "BRAKE" Indicator. With the Daytime Running Lamps (DRL) Control Module grounded through CKT 33, the module provides ground to CKT 209, lighting the "BRAKE" Indicator. System Diagnosis ^ Perform the System Check and refer to the Symptom Table for the appropriate diagnostic procedure(s). See: System Check See: Symptom Related Diagnostic Procedures/Symptom Table System Check Troubleshooting Hints PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: 1. Check I/P Fuse Block Fuse #11. If Fuse #11 is open check for a short to ground in CKT 39. 2. Check brake fluid level. If low, refer to Antilock Brake System. See: Antilock Brakes / Traction Control Systems ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures."). See: Diagrams/Diagnostic Aids ^ Refer to System Diagnosis. See: System Diagnosis Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 6821 Brake Warning Indicator: Symptom Related Diagnostic Procedures Symptom Table Chart #1 Ignition Switch Does Not Activate The BRAKE Indicator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 6822 Chart #2 Park Brake Does Not Activate The BRAKE Indicator (Base Or Twilight Sentinel) Chart #3 Park Brake Does Not Activate The BRAKE IND (With DRL) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 6823 Chart #4 BRAKE IND Stay ON W/IGN SW In RUN & Park Brake Released (Base/Twilight Sentinel) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 6824 Chart #4 BRAKE IND Stays ON W/IGN SW In RUN & Park Brake Released (W/DRL) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Brake Warning Indicator > Component Information > Testing and Inspection > Page 6825 Brake Warning Indicator: Service and Repair This lamp will be illuminated when the ignition switch is placed in the ON position. The lamp may be illuminated for as long as 30 seconds as a bulb and system check. If lamp remains illuminated or comes on while operating the vehicle, a problem in the anti-lock brake system is indicated. When lamp is illuminated, place ignition switch in OFF position, then restart engine. If lamp still remains illuminated, the anti-lock brake system should be serviced. The brake system will remain functional, but without the anti-lock function. After servicing the anti-lock brake system the lamp will automatically reset. On some models it may be necessary to operate vehicle at a speed over 18 mph to reset lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Specifications > Bore Diameter Brake Caliper: Specifications Bore Diameter Caliper Bore Diameter 2.94 in Caliper Bore Diameter 2.126 in Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Specifications > Bore Diameter > Page 6831 Brake Caliper: Specifications Tightening Specifications Brake Hose To Caliper 30 ft.lb Caliper Bleeder Screw 7 ft.lb Front Caliper Mounting Bracket 166 ft.lb Rear Bracket Mounting Bolt 70 ft.lb Rear Lower Guide Pin Bolt 16 ft.lb Rear Pivot Pin Nut 16 ft.lb Rear Upper Guide Pin Bolt 26 ft.lb Brake Hose To Caliper 33 ft.lb Caliper Bleeder Screw 115 ft.lb Caliper Mounting Bolts 38 ft.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes Brake Caliper: Service and Repair Front Disc Brakes Removal/Installation Fig. 3 Piston Compressing W/C-Clamp Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6834 Fig. 4 Caliper & Mounting Bolts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6835 Fig. 8 Caliper & Stops Clearance Inspection REMOVAL 1. Siphon enough brake fluid out of master cylinder to bring fluid level to 1/3 full to avoid fluid overflow when caliper piston is pushed back into its bore. 2. Raise vehicle and remove front wheels. 3. Using a C-clamp, as illustrated in Fig. 3, push piston back into its bore. 4. If caliper assembly is to be serviced, remove inlet fitting attaching bolt, copper washer, and inlet fitting from caliper housing. Plug opening in inlet fitting to prevent fluid loss and contamination. Do not crimp brake hose, as this may damage internal structure of hose. If only shoe and lining assemblies are to be replaced, do not disconnect brake line fitting from caliper. 5. Remove two mounting bolts, Fig. 4, and lift caliper away from disc. If only shoe and lining assemblies are to be replaced, suspend caliper from chassis using suitable hanger. Do not allow caliper to hang by brake hose. INSTALLATION 1. Position caliper over disc, lining up holes in caliper with holes in mounting bracket. If brake hose was not disconnected during removal, be sure not to kink it during installation. 2. Start mounting bolts through sleeves in inboard caliper ears and mounting bracket, making sure ends of bolts pass under ears on inboard shoe. Right and left calipers must not be interchanged. 3. Push mounting bolts through to engage holes in outboard ears. Then thread mounting bolts into bracket. 4. Tighten mounting bolts to specifications. 5. Check dimensions between each caliper stop and caliper, Fig. 8. 6. If brake hose was removed, reconnect it and bleed calipers. 7. Replace front wheels, lower vehicle and add brake fluid to master cylinder to bring level to 1/4 inch from top. Before moving vehicle, pump brake pedal several times to be sure it is firm. Do not move vehicle until a firm pedal is obtained. On some models with low drag calipers, apply approximately 175 pounds of pressure to brake pedal three times to properly seat caliper and related components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6836 Disassemble/Assemble Fig. 5 Caliper Piston Removal. Fig. 6 Boot To Piston Installation. Fig. 7 Boot To Caliper Piston Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6837 DISASSEMBLE 1. Remove caliper. Refer to Removal/Installation. 2. Clean outside of caliper, then drain brake fluid from caliper. 3. Use clean shop towels to pad interior of caliper assembly, then remove piston by directing compressed air into caliper brake hose inlet hole, Fig. 5. Use just enough air pressure to ease piston out of bore. Do not place fingers in front of piston for any reason when applying compressed air. This could result in serious personal injury. 4. Carefully pry dust boot out of bore. 5. Using a small piece of wood or plastic, remove piston seal from bore. Do not use a metal tool of any kind to remove seal as it may damage bore. 6. Remove bleeder valve. 7. Inspect piston for scoring, nicks, corrosion, and wear and replace as needed. 8. Inspect caliper housing and seal groove for corrosion, nicks, scoring and excessive wear, and use crocus cloth to polish away corrosion from housing bore. Replace caliper housing if corrosion in and around seal groove will not clean up with crocus cloth. 9. Clean all parts with denatured alcohol. Dry with unlubricated compressed air. Blow out all passages in housing and bleeder valve. ASSEMBLE 1. Lubricate caliper piston bore and new piston seal with clean brake fluid. Position seal in bore groove. Ensure seal is not twisted. 2. Lubricate piston with clean brake fluid and assemble a new boot into groove in piston so the fold faces the open end of piston, Fig. 6. 3. Using care not to unseat seal, insert piston into bore and force piston to the bottom of bore. 4. Position dust boot in caliper counterbore and install, using suitable seal installer, Fig. 7. Check boot installation to be sure retaining ring molded into boot is not bent and that boot is installed below caliper face and evenly all around. If boot is not fully installed, dirt and moisture may enter bore and cause corrosion. 5. Install brake hose in caliper using a new copper gasket. 6. Install shoes and reinstall caliper assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6838 Brake Caliper: Service and Repair Rear Disc Brakes Removal/Installation Fig. 3 Disabling Parking Brake Automatic Adjuster Mechanism Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6839 Fig. 1 Exploded View Of PBR Single Piston Rear Caliper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6840 Fig. 4 Parking Brake Free Travel Adjustment REMOVAL 1. Disable parking brake automatic adjuster as follows: a. Working from inside vehicle, remove driver seat cushion, then the parking brake lever cover screws and cover. b. Using 0.080 inch gauge wire, fabricate a tool to disengage drive pawl from sector, Fig. 3. c. Using tool mentioned above, disengage drive pawl from sector, then insert a nail through anchor plate to keep drive pawl in disengaged position. d. Pull up on lever until it aligns with pawl, then depress button until lever is fully downward. e. Visually inspect that anchor plate is fully against stud. If not, repeat procedure as needed. f. Pull front parking brake cable rearward to slacken cable at caliper assembly. 2. Raise and support vehicle, then remove tire and wheel assembly. 3. Install two wheel retaining nuts to retain rotor in position. 4. If caliper requires overhaul, remove inlet fitting attaching bolt, then disconnect inlet fitting from caliper housing. Discard the two gaskets, then plug openings in inlet fitting and caliper to prevent loss or contamination of fluid. 5. Remove caliper lever return spring. Discard spring if coils are open. 6. Disconnect parking brake cable from lever (5) and caliper bracket (8), Fig. 1. 7. Remove upper and lower guide pin bolts, then remove caliper from rotor and mounting bracket. If caliper does not require overhaul, suspend it from suspension to prevent damage to brake line. INSTALLATION 1. Install shoe and lining assemblies, if removed, as outlined previously. 2. Position caliper over rotor and onto mounting bracket, then install upper and lower guide pin bolts. Torque upper bolt to 26 ft. lbs. and lower bolt Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6841 to 16 ft. lbs. 3. Attach parking brake cable to caliper bracket and lever, then install lever return spring. 4. If removed, install inlet fitting using new gaskets, then bleed brake system. 5. If caliper was overhauled, adjust parking brake free travel as follows: a. Have an assistant apply a light load to brake pedal until rotor can no longer be turned by hand. b. Apply pressure to caliper lever in direction shown in Fig. 4. c. Measure free travel between caliper lever and housing. Free travel should be 0.024-0.028 inch. If free travel is not as specified, proceed to next step. d. Remove adjustment screw, then clean thread adhesive from threads. e. Coat threads with new adhesive, reinstall adjustment screw, then turn as required until specified free travel is obtained. Turning screw clockwise increases free travel, while counterclockwise rotation decreases travel. f. Release brake pedal, then firmly apply brake pedal three times and recheck free travel. Repeat adjustment procedure as necessary. 6. Remove nail from anchor plate installed during caliper removal procedure. 7. Apply and release parking brake three times, then lift lever upward and ensure parking brake fully engages at 7-9 clicks. 8. Release parking brake. No brake drag should exist and no gap between caliper housings and parking levers should be evident. 9. Install parking brake lever cover, screws and driver's cushion. 10. Reinstall tire and wheel assembly, then check and refill master cylinder as required. 11. Start engine and pump brake pedal several times to seat brake linings. Disassemble/Assemble Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6842 Fig. 1 Exploded View Of PBR Single Piston Rear Caliper DISASSEMBLE 1. Remove caliper. Refer to Removal/Installation. 2. Remove the two return springs from actuating collar, then pull collar out of caliper housing and remove clamp rod (28) and bushing (27), Fig. 1. discard bushing. 3. Bend back boot retainer tabs, then remove retainers (21, 31), boots (20, 25) and pushrod (22) from actuating collar. Remove preload spring (23) from retainer (31), then discard retainers and boots. 4. Use clean shop towels to pad interior of caliper assembly, then remove piston by directing compressed air into caliper brake hose inlet hole, Use just enough air pressure to ease piston out of bore. Do not place fingers in front of piston for any reason when applying compressed air. This could result in serious personal injury. 5. Using a small piece of wood or plastic, remove piston seal from bore. Do not use a metal tool of any kind to remove seal as it may damage bore. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6843 6. Remove bleeder valve cap and bleeder valve. 7. Remove seal (1), sprag clip (2) and lever (5) from pivot pin (3). Discard sprag clip. 8. Clean all metal components with suitable solvent, then dry with compressed air. 9. Inspect parking brake lever components, piston, caliper bore and mounting bracket for scoring, excessive wear or corrosion. Replace parts as necessary. CALIPER ASSEMBLE 1. Using clean brake fluid, lubricate piston seal, then install seal into caliper bore groove. Ensure seal is not twisted during installation. 2. Using clean brake fluid, lubricate caliper bore and piston. 3. Place piston into caliper bore, then push downward until fully bottomed in bore. 4. Apply lubricant provided in repair kit to actuating collar (24), then install pushrod (22), new boots (20, 25) and new retainers (21, 31) onto collar, Fig. 1. Clamp retainers firmly against collar, then bend tabs on retainer (21) to hold assembly together. 5. Reconnect preload spring (23) onto retainer (31). 6. Apply lubricant provided in repair kit to clamp rod (28), then slide rod through holes in boot (25) and actuating collar (24). Ensure boot is firmly positioned against reaction plate on clamp rod. 7. Lubricate new compliance bushing (27), then install bushing onto clamp rod (28). 8. Lubricate grooved bead of inner boot (20), boot groove in caliper housing and actuating collar with lubricant provided in repair kit. 9. Push clamp rod to bottom of piston mating hole, then pull actuating collar (24) and seat inner boot (20) into boot groove in caliper housing. 10. Ensure pushrod (22) is positioned in hole in caliper housing, then install bleeder cap and valve. 11. If removed, install pivot pin (3) and new nut (12) onto caliper, torque nut to 16 ft. lbs., then lubricate parking brake lever (5) and pivot pin. 12. Install pivot pin seal (1), parking brake lever and new sprag clip (2), ensuring teeth of sprag clip face away from lever, then snap seal cap over pivot pin. 13. Install the two collar return springs (26) onto retainer (31). Ensure retainer enters springs at end of second coil. 14. Install adjustment screw (11) into caliper housing until actuating collar is parallel to piston bore face of housing. 15. Lubricate guide pins with suitable grease, then slide boots onto pins. 16. Fill boots with grease, then install into mounting bracket. Ensure boots are properly positioned in grooves in pins and mounting bracket. 17. Install caliper and bleed brake system, then adjust parking brake free travel under Adjustments. Refer to Parking Brake System. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Pad > Component Information > Service and Repair > Front Disc Brakes Brake Pad: Service and Repair Front Disc Brakes Fig. 2 Brake Shoe Ear Crimping REMOVAL 1. Remove caliper assembly from steering knuckle as described in Brake Caliper/Removal/Installation. 2. Remove inboard shoe. Dislodge outboard shoe and position caliper on front suspension so the brake hose will not support the weight of the caliper. 3. Remove shoe support spring from piston. 4. Remove two sleeves from inboard ears of caliper. 5. Remove four rubber bushings from grooves in each of caliper ears. INSTALLATION 1. Lubricate new sleeves, rubber bushings, bushing grooves and mounting bolt ends with Delco Silicone Lube or its equivalent. 2. Install new bushings and sleeves in caliper ears. Position sleeve so that the end toward the shoe is flush with machined surface of the ear. 3. Install shoe support spring by positioning single tang end of spring into notch cut at top of inboard shoe. Press remaining end of spring over bottom edge of shoe until shoe is engaged securely. 4. Position inboard shoe with spring attached into caliper with ear end facing downward and bottom end facing upward with spring resting on inside diameter of piston. Press downward on both ends of shoe until shoe contacts piston and support spring contacts piston inside diameter. Some inboard replacement brake pads incorporate wear sensors and have a specific left and righthand assembly. Properly installed, wear sensor will face toward rear of caliper. 5. Position outboard shoe in caliper with shoe ears over caliper ears and tab at bottom of shoe engaged in caliper cutout. 6. With shoes installed, lift caliper and rest bottom edge of outboard lining on outer edge of brake disc to be sure there is no clearance between outboard shoe tab and caliper abutment. 7. Install caliper and tighten mounting bolts to specifications. 8. Clinch upper ears of outboard shoe by positioning pliers with one jaw on top of upper ear and one jaw in notch on bottom shoe opposite ear, Fig. 2. Ears are to be flat against caliper housing with no radial clearance. If clearance exists, repeat clinching procedure. Before moving vehicle, pump brake pedal several times to be sure it is firm. Do not move vehicle until a firm pedal is obtained. On some models with low drag calipers, apply approximately 175 pounds of pressure to brake pedal three times to properly seat caliper and related components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Pad > Component Information > Service and Repair > Front Disc Brakes > Page 6848 Brake Pad: Service and Repair Rear Disc Brakes Fig. 2 Piston Compressing In Caliper Bore REMOVAL 1. Remove 2/3 of the total brake fluid capacity from master cylinder reservoir. 2. Raise and support vehicle, then remove tire and wheel assembly. 3. Install two wheel retaining nuts to retain rotor in position. 4. Position one end of a suitable C-clamp against inlet fitting bolt, and the other end against outboard shoe and lining, then tighten clamp as shown, Fig. 2, until piston fully bottoms in caliper bore. 5. Remove upper guide pin bolt and discard. 6. Loosen lower guide pin bolt, then pivot caliper downward on lower guide pin bolt to expose shoe & lining assemblies. Use care to avoid damaging brake hose. 7. Remove shoes and linings from mounting bracket. INSTALLATION 1. Install outboard shoe and lining onto mounting bracket, ensuring insulator on shoe is positioned toward caliper housing. 2. Install inboard shoe and lining. Ensure wear sensor is positioned nearest caliper piston. When properly installed, sensor should be in trailing position when wheel is rotated in forward direction. 3. Pivot caliper into position over shoes and linings. Ensure springs on outboard shoe do not protrude through inspection hole in housing. If protrusion is evident, lift caliper housing and readjust position of outboard shoe and lining. 4. Install new upper guide pin bolt and torque to 26 ft. lbs., then torque lower bolt to 16 ft. lbs. 5. Fill master cylinder to proper level, then pump brake pedal firmly and slowly three times to bring pads into contact with brake rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information Brake Rotor/Disc: Technical Service Bulletins Brakes - Rotor Lateral Runout Correction Information Bulletin No.: 01-05-23-001B Date: January 31, 2008 INFORMATION Subject: Brake Align(R) System for Brake Rotor Lateral Runout Correction Models: 2008 and Prior Passenger Cars Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 01-05-23-001A (Section 05 - Brakes). This bulletin is being issued to update General Motors position on correcting brake rotor lateral runout (Refer to Corporate Bulletin Number 00-05-22-002B for additional brake rotor service procedures). Certain conditions may apply to individual vehicles regarding specific repairs. Refer to those specific repairs in applicable service bulletins. Make sure other possible sources of brake pulsation, such as ABS pedal feedback, have been addressed before checking rotor runout. Anytime a new or refinished rotor is installed on a vehicle, the rotor must have .050 mm (.002 in) or less of lateral runout. This specification is important to prevent comebacks for brake pulsation. Until now, the only acceptable methods to correct brake rotor runout were to index or replace the rotor or to refinish the rotor using an on-vehicle brake lathe. GM has approved a new technology for the correction of lateral runout on new or refinished rotors. This new method is called Brake align(R)*. It will allow the technician to meet the .050 mm (.002 in) or less requirement for lateral runout by installing a specially selected, tapered correction plate between the rotor and the hub. The Brake Align(R) Correction system does NOT require the use of an on-vehicle brake lathe to correct for lateral runout. *We believe this source and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such items which may be available from other sources. The Brake Align(R) Starter Kit will include an ample supply of Correction Plates, in various correction sizes, that will cover most current GM passenger car applications. It will also include a Brake Align(R) tool kit containing a dial indicator and retaining washers along with other useful tools. Service Procedure Follow all the procedures referred to in Corporate Bulletin Number 00-05-22-002B. Dealers who have purchased the Brake Align(R) Starter Kit may use the following simplified runout correction procedure: The existing rotors must first be machined on an approved, well-maintained bench lathe to guarantee smooth, flat, and parallel surfaces. Should the rotors require replacement, please note that it is not necessary to machine new rotors. Make sure all the mating surfaces of the rotor and the hub are clean, using the J 42450-A wheel Hub Cleaning Kit. Mount the new or refinished rotor onto the vehicle hub using the retaining washers provided in the kit. Do not reinstall the caliper or wheel at this time. Tighten all the wheel nuts to the proper specification, using J 39544 Torque Socket or the equivalent. Fasten the dial indicator to the steering knuckle so that the indicator needle contacts the rotor friction surface approximately 12.7 mm (1/2 in) from the rotors outer edge. Rotate the rotor and observe the total lateral runout. Index the rotor on the hub to achieve the lowest amount of lateral runout. This will require removal and reassembly of the rotor until the lowest total lateral runout reading is obtained. If this reading is .050 mm (.002 in) or less, the assembled rotor is within specification. The brake system may be reassembled. If total lateral runout is greater than .050 mm (.002 in), proceed with determining the correct Brake Align(R) Correction as follows: Rotate the rotor to locate the lowest dial indicator reading and set the dial to zero. Rotate the rotor to determine and locate the highest amount of lateral runout. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6853 Note the AMOUNT and LOCATION of the "high spot" on the rotor and mark the closest wheel stud relative to this location. Remove the rotor. Select the appropriate Brake Align(R) Runout Correction Plate for this vehicle using the Application Chart. Make sure the selection corrects the amount of runout that was diagnosed. Never attempt to stack two or more Correction Plates together on one hub. Never attempt to re-use a previously installed Correction Plate. Following the Brake Align(R) procedures and diagram, install the Correction Plate onto the vehicle between the hub and the rotor. The V-notch in the Correction Plate is to be installed and aligned with the noted location of the "high spot" on the vehicle hub and marked wheel stud. Install the rotor onto the vehicle with the Correction Plate placed between the hub and the rotor. Be sure to install the rotor onto the hub in the same location as identified in Step 7. The rotor should then be secured onto the hub and tightened to the proper specification. The rotor should be dial indicated once more to assure that the rotor is now within specification. The brake system is now ready for the remaining service and assembly. Once the caliper has been installed, check to ensure that the rotor rotates freely. Parts Information Brake Align(R) Runout Correction Plates are available through the suppliers shown. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6854 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6855 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6856 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6857 Brake Align Order Form Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6858 Brake Rotor/Disc: Technical Service Bulletins Brakes - Rotor & Hub Flange Cleaning Tool Revision File In Section: 5 - Brakes Bulletin No.: 73-50-37 Date: January, 1998 INFORMATION Subject: Revision to J 42450 Tool; Proper Brake Rotor and Hub Flange Surface Cleaning Models: 1998 and Prior Passenger Cars and Light Duty Trucks - with Disc Brakes (Rotor and Hub Separate) This bulletin is being revised to update the following text. This bulletin is being issued to inform the dealer about a revision to tool J 42450 and reinforce the need for proper hub flange and brake rotor mating surface cleaning during service. Tool J 42450 is a cleaning pad arbor and pad system that fits over the wheel stud and cleans the portion of the hub surface that is very difficult to reach with normal rotary cleaning pads. Tool J 42450 is being revised to J 42450-A to improve the hook and loop material retention. Any dealer experiencing problems with tool J 42450 should contact Kent-Moore at 1-800-345-2233 for a revised arbor at no charge. Anytime the brake rotor has been separated from the hub bearing flange or if rotor machining is necessary, the rotor and hub should be marked to maintain the original position. Clean the hub flange of all dirt and foreign material using special tool J 42450 or J 42450-A. Clean both sides of the brake rotor hub using an aggressive (80 grit) abrasive sanding pad on a rotary disc. Properly cleaning the rotor surfaces before rotor machining or reassembly ensures that dirt and corrosion will not add lateral runout to the rotor. Proper cleaning of the hub flange will also minimize the stack-up of lateral runout. On reassembly, the rotor should be reinstalled aligning the marks made on disassembly. Always use a torque wrench or the appropriate Torque Socket found in J 39544-KIT on an impact wrench when installing the wheel and tire assembly. Torque all wheel nuts using the correct sequence and torque. Refer to the Tire and Wheel Sub-Section in the applicable Service Manual. Excessive torque or torque variation between wheel nuts may cause distortion of the hub and rotor mating surface. This distortion may cause lateral runout and lead to brake pulsation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6859 Technical Service Bulletin # 23-50-05B Date: 971101 Brakes - Rotor Warranty Service Procedure File In Section: 5 - Brakes Bulletin No.: 23-50-05B Date: November, 1997 INFORMATION Subject: Brake Rotor Warranty Service Procedure Model: 1994-98 GM Passenger Cars This bulletin outlines GM's procedures for brake rotor service for all applicable GM passenger cars and supersedes Corporate Bulletin Number 23-50-05A Section 5 - Brakes). Important: Rotors should only be turned when one or more of the following rotor surface conditions exist: 1. Severe Scoring - depth in excess of 1.5 mm (0.060 in.). 2. Pulsation Concerns from: a. Thickness variation in excess of 0.025 mm (0.001 in.). b. Corrosion on rotor braking surfaces. Rotors are NOT to be resurfaced in an attempt to correct: 1. Noise/squeal. 2. Cosmetic corrosion. 3. Routine pad replacement. 4. Discoloration and/or "hard spots". Explanation of Brake Rotor Warranty Service Procedure Research and testing has determined: 1. Rotor refacing during normal pad replacement is not necessary. 2. Rotor refacing for cosmetic corrosion is unnecessary. Clean-up of braking surfaces can be accomplished by 10-15 moderate stops from 62-75 km/h (35-40 mph) with cooling time between stops. 3. Rotor service is ineffective in correcting BRAKE SQUEAL, and/or PREMATURE LINING WEAR OUT, and should NOT be used to address these conditions. 4. When installing new rotors, DO NOT reface them. 5. Ensure bearing flanges are free of corrosion when installing rotors to prevent inducing lateral runout. Use Kent Moore tool J 42450 to clean the corrosion around the wheel studs. Brake Service Techniques EVERY brake service should include: 1. Clean and lube all metal-to-metal contact points (i.e.; caliper to knuckle, pad to knuckle, etc.). 2. Clean and lube slide pins. 3. Set correct clearances - caliper to knuckle, etc. 4. Clean rotor and hub mounting surfaces. Use Kent Moore tool J 42450 to clean around wheel studs. Pulsation Brake pulsation concerns may result from two basic conditions: 1. Thickness variation. 2. Excessive corrosion. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6860 Rotor thickness variation is the result of uneven rotor wear caused by excessive lateral runout (>0.076 mm; >0.003 in.). Lateral runout can be induced by: 1. Distortion of the braking surface by applying uneven and/or excessive wheel nut torque. (This could be the result of a recent tire change, rotation, etc.). 2. Improperly refacing rotors. Brake Noise Important: SOME BRAKE NOISE IS NORMAL. Brake noise is caused by a "slip stick" type vibration of brake components. Some intermittent brake noise may be normal. Performing 3-4 aggressive stops may temporarily reduce or eliminate most brake squeal. If the noise persists, a brake dampening compound may be applied to the back of each pad. Use Permatex Disc Brake Quiet # 126HB or equivalent. Also, clean and lube all metal-to-metal contact areas between pads, pad guides, caliper and knuckles with a thin layer of high temperature silicone grease. This allows parts to slide freely and not vibrate when moving relative to each other. Rotor Grooving Excessive grooving can be caused by foreign material in contact with the rotor, but most often rotor grooving is the result of normal brake wear. DO NOT RESURFACE ROTORS FOR LIGHT GROOVING. Resurface rotors only when grooves of 1.5 mm (0.060 in.) or deeper are present. A dime may be used to determine disc brake groove depth. Place a dime in the groove, with Roosevelt's head toward the groove. If the dime goes into the groove beyond the top of his head, the groove exceeds 1.5 mm (0.060 in.) and the rotor should be serviced. (In Canada, if any portion of the letters of "In Canada" are covered, the rotor should serviced.) It the groove is too narrow for the dime to be inserted, it is not a cause for concern. High Pedal Effort Follow Service Manual diagnostic procedures for this condition. Service rotors if they have been recently resurfaced. (The surface finish may be out-of-specification). Lightly Rusted Rotors Light surface rust on rotor braking surfaces is often cosmetic and can be eliminated during a few normal driving stops. Rusting may occur when a vehicle is not driven for extended periods. Rotors with surface rust on unsold new cars can usually be burnished clean by performing 15 moderate stops from 62-75 km/h (35-40 mph) with cooling time between stops. Facts About Brake Service ^ Original equipment rotor surfaces are ground to ensure smooth finish and parallelism between mounting and friction surfaces. New rotors should not be resurfaced before installation. ^ Improper tightening of wheel nuts can induce lateral runout (distortion of braking surfaces) which will lead to uneven wear. As high spots are worn down, resulting thickness variation will cause brake pulsation. ^ Ensure wheel bearing flange is clean and free of corrosion before installing new rotors. A new essential tool (Kent Moore tool J 42450) will soon be sent to all dealers. This tool makes it easier to clean corrosion around the wheel studs. ^ Always mark the position of rotor on the hub before removal, and reinstall the rotor in the same position. ^ Rotors with perceived hard spots or discoloration should not be serviced. These conditions are normal. ^ Installation of new rotors does not require pad replacement. Do NOT replace pads unless their condition requires it. ^ It is NOT necessary to replace rotors in pairs. Rotors may be serviced individually. ^ A TORQUE LIMITING SOCKET OR TORQUE WRENCH MUST BE USED to insure that the wheel nuts are tightened to specification. This should be done in 3 steps using the star pattern. 1. Snug the nuts down by hand. 2. Using the star pattern and a torque limiting socket or torque wrench, tighten the wheel nuts to about half the final torque. 3. Tighten the wheel nuts to specification using the star pattern and a torque limiting socket or torque wrench. ^ NEVER use lubricants or penetrating fluids on wheel studs, nuts, or mounting surfaces. Wheel nuts, studs, and mounting surfaces must be clean and dry. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Brakes - Rotor Lateral Runout Correction Information > Page 6861 Brake Rotor/Disc: Technical Service Bulletins Brakes - Revised Rear Rotor Specifications File In Section: 5 - Brakes Bulletin No.: 73-50-12 Date: April, 1997 SERVICE MANUAL UPDATE Subject: Section 5B2 - Revised Rear Disc Brake Rotor Specifications Models: 1994-96 Chevrolet Caprice, Impala SS This bulletin is being issued to revise the rear disc brake rotor specifications listed in Section 5B2 of the Service Manual. The correct specifications for the rotor are: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Technical Service Bulletins > Page 6862 Brake Rotor/Disc: Specifications Nominal Thickness 1.043 in Minimum Refinish Thickness 0.965 in Thickness Variation (Parallelism) 0.0005 in Lateral Runout (T.I.R.) 0.003 in Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Service and Repair > Front Disc Brakes Brake Rotor/Disc: Service and Repair Front Disc Brakes 1. Remove caliper assembly from steering knuckle as described in Brake Caliper/Removal/Installation. 2. On models with anti-lock brakes, proceed as follows: a. Remove wheel speed sensor retaining bolt from rear side of steering knuckle. b. Remove wheel speed sensor from steering knuckle and position aside. 3. On all models, remove wheel bearing lubricant cap from center of rotor. 4. Remove cotter pin, nut and washer from steering knuckle assembly. 5. Carefully pull brake rotor from steering knuckle. 6. Reverse procedure to install, prior to installing cotter pin onto steering knuckle, adjust wheel bearing as follows: a. Torque nut to 21 ft. lbs. while turning brake rotor clockwise. This will remove any grease or burrs which may cause excessive wheel bearing play. b. Back off nut to a just loose position. c. Hand tighten nut until next slot. d. Install cotter pin and wheel bearing lubricant cap. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Disc Brake System > Brake Rotor/Disc > Component Information > Service and Repair > Front Disc Brakes > Page 6865 Brake Rotor/Disc: Service and Repair Rear Disc Brakes 1. Remove caliper as described in Brake Caliper/Removal/Installation. 2. Remove caliper mounting bracket attaching bolts, then the mounting bracket. 3. Remove rotor from hub and bearing assembly. 4. Reverse procedure to install, adjust parking. brake as described under Adjustments. Refer to Parking Brake System. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Drum Brake System > Wheel Cylinder > Component Information > Technical Service Bulletins > Brakes - Wheel Cylinder Inspection Guidelines Wheel Cylinder: Technical Service Bulletins Brakes - Wheel Cylinder Inspection Guidelines Bulletin No.: 03-05-24-001A Date: March 21, 2005 INFORMATION Subject: Service Information Regarding Rear Brake Drum Wheel Cylinder Inspections Models: 2005 and Prior GM Passenger Cars and Trucks 2005 and Prior Saturn Vehicles with Rear Drum Brakes Supercede: This bulletin is being revised add model years and include all GM vehicles. Please discard Corporate Bulletin Number 03-05-24-001 (Section 03 - Suspension). This bulletin provides information on proper inspection of rear drum brake wheel cylinders. Important: It is not recommended that dust boots be removed during inspection processes as dirt and debris could contaminate the wheel cylinder bore causing premature wear of the wheel cylinder. In addition, most bores should look damp and some lubricant may drip out from under the boot as a result of lubricant being present. All rear drum brake wheel cylinders are assembled with a lubricant to aid in assembly, provide an anti-corrosion coating to the cylinder bore, and lubricate internal rubber components. As a result of this lubrication process, it is not uncommon for some amount of lubricant to accumulate at the ends of the cylinder under the dust boot. Over time, the lubricant may work its way to the outside of the boot and cause an area of the boot to look damp. Evidence of a damp area on the boot does not indicate a leak in the cylinder. However, if there is excessive wetness (i.e. drips) coming from the boot area of the wheel cylinder, it could indicate a brake hydraulic fluid leak requiring wheel cylinder replacement. (Refer to the Wheel Cylinder Replacement procedures in the appropriate Service Manual.) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Drum Brake System > Wheel Cylinder > Component Information > Technical Service Bulletins > Page 6871 Wheel Cylinder: Specifications Wheel Cylinder Bore Diameter 1 in Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Drum Brake System > Wheel Cylinder > Component Information > Technical Service Bulletins > Page 6872 Wheel Cylinder: Service and Repair Fig. 33 Exploded View Of Wheel Cylinder 1. Raise and support vehicle. 2. Remove wheel, drum and brake shoes. 3. Disconnect hydraulic line at wheel cylinder. Do not pull metal line away from cylinder, as this may kink or bend line. Line will separate from cylinder when cylinder is moved away from brake backing plate. 4. Remove wheel cylinder-to-brake plate attaching screws, then the wheel cylinder. 5. Remove boots, pistons, springs and cups from cylinder, Fig. 33. 6. Clean all parts with brake fluid. 7. Inspect cylinder bore. A scored bore may be honed as long as the diameter is not increased by more than .005 inch. Replace worn or damaged parts as necessary. 8. Ensure hands are clean before proceeding with assembly. Lubricate cylinder wall and rubber cups with brake fluid, then install springs, cups, pistons and boots in housing. 9. Wipe end of hydraulic line to remove any foreign matter, then place wheel cylinder in position. Enter tubing into cylinder and start threads on fitting. 10. Secure cylinder to backing plate, then complete tightening of tubing fitting. 11. Install brake shoes, drum and wheel. 12. Bleed system as outlined previously, then adjust brakes. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Bleeding > System Information > Service and Repair > With ABS System Brake Bleeding: Service and Repair With ABS System Manual Bleeding Fig. 210 Brake System Manual Bleed. NOTE: Pressure bleeding is recommended for all hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure. CAUTION: Brake fluid damages painted surfaces. Immediately clean any spilled fluid. 1. Remove vacuum reserve by pumping brakes several times with engine off. 2. Fill master cylinder reservoir with clean brake fluid. Check fluid level often during bleeding procedure; do not let reservoir fall below half full. 3. If necessary, bleed master cylinder as follows: a. Disconnect master cylinder forward brake line connection until fluid flows from reservoir. Reconnect and tighten brake line. b. Instruct an assistant to slowly depress brake pedal one time and hold. c. Crack open front brake line connection again, purging air from cylinder. d. Retighten connection and slowly release brake pedal. e. Wait 15 seconds, then repeat until all air is purged. f. Bleed the rearward (nearest the cowl) brake line connection by repeating preceding steps. 4. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 5. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleed Sequence. See: Wheel Bleed Sequence 6. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 210. Ensure end of tube is submerged in clean brake fluid. 7. Instruct an assistant to slowly depress brake pedal one time and hold. 8. Crack open bleeder valve, purging air from cylinder. Retighten bleeder screw and slowly release pedal. 9. Wait 15 seconds, then repeat preceding bleed steps. Repeat these steps until all air is bled from system. Pressure Bleeding Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6878 Fig. 210 Brake System Manual Bleed. Fig. 21 Installing Pressure Bleeder Adapter 1. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 2. Using a diaphragm type pressure bleeder, install suitable bleeder adapter to master cylinder, Fig. 211. 3. Charge bleeder ball to 20-25 psi. 4. Connect pressure bleeder line to adapter. 5. Open line valve on pressure bleeder, then depress bleed-off valve on adapter until a small amount of brake fluid is released. 6. Raise and support vehicle. 7. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. See: Wheel Bleed Sequence 8. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 210. Ensure end of tube is submerged in clean brake fluid. 9. Open bleeder valve 1/2 to 3/4 turn and allow fluid to flow into container until all air is purged from line. Wheel Bleed Sequence If manual bleeding, RR-LR-RF-LF; if pressure bleeding, bleed front brakes together and rear brakes together. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6879 Brake Bleeding: Service and Repair Without ABS System Manual Fig. 210 Brake System Manual Bleed. NOTE: Pressure bleeding is recommended for all hydraulic systems. However, if a pressure bleeder is unavailable, use the following procedure. Brake fluid damages painted surfaces. Immediately clean any spilled fluid. 1. Remove vacuum reserve by pumping brakes several times with engine off. 2. Fill master cylinder reservoir with clean brake fluid. Check fluid level often during bleeding procedure; do not let reservoir fall below half full. 3. If necessary, bleed master cylinder as follows: a. Disconnect master cylinder forward brake line connection until fluid flows from reservoir. Reconnect and tighten brake line. b. Instruct an assistant to slowly depress brake pedal one time and hold. c. Crack open front brake line connection again, purging air from cylinder. d. Retighten connection and slowly release brake pedal. e. Wait 15 seconds, then repeat until all air is purged. f. Bleed the rearward (nearest the cowl) brake line connection by repeating steps a through e. 4. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 5. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. 6. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 16. Ensure end of tube is submerged in clean brake fluid. 7. Instruct an assistant to slowly depress brake pedal one time and hold. 8. Crack open bleeder valve, purging air from cylinder. Retighten bleeder screw and slowly release pedal. 9. Wait 15 seconds, then repeat steps 7 and 8. Repeat these steps until all air is bled from system. Pressure Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6880 Fig. 21 Installing Pressure Bleeder Adapter Fig. 210 Brake System Manual Bleed. 1. Loosen, then slightly retighten bleeder valves at all four wheels. Repair any broken, stripped or frozen valves at this time. 2. Using a diaphragm type pressure bleeder, install suitable bleeder adapter to master cylinder, Fig. 17. 3. Charge bleeder ball to 20-25 psi. 4. Connect pressure bleeder line to adapter. 5. Open line valve on pressure bleeder, then depress bleed-off valve on adapter until a small amount of brake fluid is released. 6. Raise and support vehicle. 7. Proceed to appropriate wheel first and follow set sequence according to Wheel Bleeding Sequence. 8. Place transparent tube over bleeder valve, then allow tube to hang down into transparent container, Fig. 16. Ensure end of tube is submerged in clean brake fluid. 9. Open bleeder valve 1/2 to 3/4 turn and allow fluid to flow into container until all air is purged from line. Front Disc Brakes NOTE: Pressure bleeding is recommended for all hydraulic disc brake systems. The disc brake hydraulic system can be bled manually or with pressure bleeding equipment. On vehicles with disc brakes the brake pedal will require more pumping and frequent checking of fluid level in master cylinder during bleeding operation. Never use brake fluid that has been drained from hydraulic system when bleeding the brakes. Be sure the disc brake pistons are returned to their normal positions and that the shoe and lining assemblies are properly seated. Before driving the vehicle, check brake operation to be sure that a firm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Bleeding > System Information > Service and Repair > With ABS System > Page 6881 pedal has been obtained. Rear Disc Brakes NOTE: Pressure bleeding is recommended for all hydraulic disc brake systems. The disc brake hydraulic system can be bled manually or with pressure bleeding equipment. On vehicles with disc brakes the brake pedal will require more pumping and frequent checking of fluid level in master cylinder during bleeding operation. Never use brake fluid that has been drained from hydraulic system when bleeding the brakes. Be sure the disc brake pistons are returned to their normal positions and that the shoe and lining assemblies are properly seated. Before driving the vehicle, check brake operation to be sure that a firm pedal has been obtained. Wheel Bleeding Sequence Rear wheel drive models: if manual bleeding, RR-LR-RF-LF; if pressure bleeding, bleed front brakes together and rear brakes together. Front wheel drive models: RR-LF-LR-RF Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Specifications > Bore Diameter Brake Caliper: Specifications Bore Diameter Caliper Bore Diameter 2.94 in Caliper Bore Diameter 2.126 in Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Specifications > Bore Diameter > Page 6886 Brake Caliper: Specifications Tightening Specifications Brake Hose To Caliper 30 ft.lb Caliper Bleeder Screw 7 ft.lb Front Caliper Mounting Bracket 166 ft.lb Rear Bracket Mounting Bolt 70 ft.lb Rear Lower Guide Pin Bolt 16 ft.lb Rear Pivot Pin Nut 16 ft.lb Rear Upper Guide Pin Bolt 26 ft.lb Brake Hose To Caliper 33 ft.lb Caliper Bleeder Screw 115 ft.lb Caliper Mounting Bolts 38 ft.lb Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes Brake Caliper: Service and Repair Front Disc Brakes Removal/Installation Fig. 3 Piston Compressing W/C-Clamp Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6889 Fig. 4 Caliper & Mounting Bolts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6890 Fig. 8 Caliper & Stops Clearance Inspection REMOVAL 1. Siphon enough brake fluid out of master cylinder to bring fluid level to 1/3 full to avoid fluid overflow when caliper piston is pushed back into its bore. 2. Raise vehicle and remove front wheels. 3. Using a C-clamp, as illustrated in Fig. 3, push piston back into its bore. 4. If caliper assembly is to be serviced, remove inlet fitting attaching bolt, copper washer, and inlet fitting from caliper housing. Plug opening in inlet fitting to prevent fluid loss and contamination. Do not crimp brake hose, as this may damage internal structure of hose. If only shoe and lining assemblies are to be replaced, do not disconnect brake line fitting from caliper. 5. Remove two mounting bolts, Fig. 4, and lift caliper away from disc. If only shoe and lining assemblies are to be replaced, suspend caliper from chassis using suitable hanger. Do not allow caliper to hang by brake hose. INSTALLATION 1. Position caliper over disc, lining up holes in caliper with holes in mounting bracket. If brake hose was not disconnected during removal, be sure not to kink it during installation. 2. Start mounting bolts through sleeves in inboard caliper ears and mounting bracket, making sure ends of bolts pass under ears on inboard shoe. Right and left calipers must not be interchanged. 3. Push mounting bolts through to engage holes in outboard ears. Then thread mounting bolts into bracket. 4. Tighten mounting bolts to specifications. 5. Check dimensions between each caliper stop and caliper, Fig. 8. 6. If brake hose was removed, reconnect it and bleed calipers. 7. Replace front wheels, lower vehicle and add brake fluid to master cylinder to bring level to 1/4 inch from top. Before moving vehicle, pump brake pedal several times to be sure it is firm. Do not move vehicle until a firm pedal is obtained. On some models with low drag calipers, apply approximately 175 pounds of pressure to brake pedal three times to properly seat caliper and related components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6891 Disassemble/Assemble Fig. 5 Caliper Piston Removal. Fig. 6 Boot To Piston Installation. Fig. 7 Boot To Caliper Piston Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6892 DISASSEMBLE 1. Remove caliper. Refer to Removal/Installation. 2. Clean outside of caliper, then drain brake fluid from caliper. 3. Use clean shop towels to pad interior of caliper assembly, then remove piston by directing compressed air into caliper brake hose inlet hole, Fig. 5. Use just enough air pressure to ease piston out of bore. Do not place fingers in front of piston for any reason when applying compressed air. This could result in serious personal injury. 4. Carefully pry dust boot out of bore. 5. Using a small piece of wood or plastic, remove piston seal from bore. Do not use a metal tool of any kind to remove seal as it may damage bore. 6. Remove bleeder valve. 7. Inspect piston for scoring, nicks, corrosion, and wear and replace as needed. 8. Inspect caliper housing and seal groove for corrosion, nicks, scoring and excessive wear, and use crocus cloth to polish away corrosion from housing bore. Replace caliper housing if corrosion in and around seal groove will not clean up with crocus cloth. 9. Clean all parts with denatured alcohol. Dry with unlubricated compressed air. Blow out all passages in housing and bleeder valve. ASSEMBLE 1. Lubricate caliper piston bore and new piston seal with clean brake fluid. Position seal in bore groove. Ensure seal is not twisted. 2. Lubricate piston with clean brake fluid and assemble a new boot into groove in piston so the fold faces the open end of piston, Fig. 6. 3. Using care not to unseat seal, insert piston into bore and force piston to the bottom of bore. 4. Position dust boot in caliper counterbore and install, using suitable seal installer, Fig. 7. Check boot installation to be sure retaining ring molded into boot is not bent and that boot is installed below caliper face and evenly all around. If boot is not fully installed, dirt and moisture may enter bore and cause corrosion. 5. Install brake hose in caliper using a new copper gasket. 6. Install shoes and reinstall caliper assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6893 Brake Caliper: Service and Repair Rear Disc Brakes Removal/Installation Fig. 3 Disabling Parking Brake Automatic Adjuster Mechanism Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6894 Fig. 1 Exploded View Of PBR Single Piston Rear Caliper Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6895 Fig. 4 Parking Brake Free Travel Adjustment REMOVAL 1. Disable parking brake automatic adjuster as follows: a. Working from inside vehicle, remove driver seat cushion, then the parking brake lever cover screws and cover. b. Using 0.080 inch gauge wire, fabricate a tool to disengage drive pawl from sector, Fig. 3. c. Using tool mentioned above, disengage drive pawl from sector, then insert a nail through anchor plate to keep drive pawl in disengaged position. d. Pull up on lever until it aligns with pawl, then depress button until lever is fully downward. e. Visually inspect that anchor plate is fully against stud. If not, repeat procedure as needed. f. Pull front parking brake cable rearward to slacken cable at caliper assembly. 2. Raise and support vehicle, then remove tire and wheel assembly. 3. Install two wheel retaining nuts to retain rotor in position. 4. If caliper requires overhaul, remove inlet fitting attaching bolt, then disconnect inlet fitting from caliper housing. Discard the two gaskets, then plug openings in inlet fitting and caliper to prevent loss or contamination of fluid. 5. Remove caliper lever return spring. Discard spring if coils are open. 6. Disconnect parking brake cable from lever (5) and caliper bracket (8), Fig. 1. 7. Remove upper and lower guide pin bolts, then remove caliper from rotor and mounting bracket. If caliper does not require overhaul, suspend it from suspension to prevent damage to brake line. INSTALLATION 1. Install shoe and lining assemblies, if removed, as outlined previously. 2. Position caliper over rotor and onto mounting bracket, then install upper and lower guide pin bolts. Torque upper bolt to 26 ft. lbs. and lower bolt Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6896 to 16 ft. lbs. 3. Attach parking brake cable to caliper bracket and lever, then install lever return spring. 4. If removed, install inlet fitting using new gaskets, then bleed brake system. 5. If caliper was overhauled, adjust parking brake free travel as follows: a. Have an assistant apply a light load to brake pedal until rotor can no longer be turned by hand. b. Apply pressure to caliper lever in direction shown in Fig. 4. c. Measure free travel between caliper lever and housing. Free travel should be 0.024-0.028 inch. If free travel is not as specified, proceed to next step. d. Remove adjustment screw, then clean thread adhesive from threads. e. Coat threads with new adhesive, reinstall adjustment screw, then turn as required until specified free travel is obtained. Turning screw clockwise increases free travel, while counterclockwise rotation decreases travel. f. Release brake pedal, then firmly apply brake pedal three times and recheck free travel. Repeat adjustment procedure as necessary. 6. Remove nail from anchor plate installed during caliper removal procedure. 7. Apply and release parking brake three times, then lift lever upward and ensure parking brake fully engages at 7-9 clicks. 8. Release parking brake. No brake drag should exist and no gap between caliper housings and parking levers should be evident. 9. Install parking brake lever cover, screws and driver's cushion. 10. Reinstall tire and wheel assembly, then check and refill master cylinder as required. 11. Start engine and pump brake pedal several times to seat brake linings. Disassemble/Assemble Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6897 Fig. 1 Exploded View Of PBR Single Piston Rear Caliper DISASSEMBLE 1. Remove caliper. Refer to Removal/Installation. 2. Remove the two return springs from actuating collar, then pull collar out of caliper housing and remove clamp rod (28) and bushing (27), Fig. 1. discard bushing. 3. Bend back boot retainer tabs, then remove retainers (21, 31), boots (20, 25) and pushrod (22) from actuating collar. Remove preload spring (23) from retainer (31), then discard retainers and boots. 4. Use clean shop towels to pad interior of caliper assembly, then remove piston by directing compressed air into caliper brake hose inlet hole, Use just enough air pressure to ease piston out of bore. Do not place fingers in front of piston for any reason when applying compressed air. This could result in serious personal injury. 5. Using a small piece of wood or plastic, remove piston seal from bore. Do not use a metal tool of any kind to remove seal as it may damage bore. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Caliper > Component Information > Service and Repair > Front Disc Brakes > Page 6898 6. Remove bleeder valve cap and bleeder valve. 7. Remove seal (1), sprag clip (2) and lever (5) from pivot pin (3). Discard sprag clip. 8. Clean all metal components with suitable solvent, then dry with compressed air. 9. Inspect parking brake lever components, piston, caliper bore and mounting bracket for scoring, excessive wear or corrosion. Replace parts as necessary. CALIPER ASSEMBLE 1. Using clean brake fluid, lubricate piston seal, then install seal into caliper bore groove. Ensure seal is not twisted during installation. 2. Using clean brake fluid, lubricate caliper bore and piston. 3. Place piston into caliper bore, then push downward until fully bottomed in bore. 4. Apply lubricant provided in repair kit to actuating collar (24), then install pushrod (22), new boots (20, 25) and new retainers (21, 31) onto collar, Fig. 1. Clamp retainers firmly against collar, then bend tabs on retainer (21) to hold assembly together. 5. Reconnect preload spring (23) onto retainer (31). 6. Apply lubricant provided in repair kit to clamp rod (28), then slide rod through holes in boot (25) and actuating collar (24). Ensure boot is firmly positioned against reaction plate on clamp rod. 7. Lubricate new compliance bushing (27), then install bushing onto clamp rod (28). 8. Lubricate grooved bead of inner boot (20), boot groove in caliper housing and actuating collar with lubricant provided in repair kit. 9. Push clamp rod to bottom of piston mating hole, then pull actuating collar (24) and seat inner boot (20) into boot groove in caliper housing. 10. Ensure pushrod (22) is positioned in hole in caliper housing, then install bleeder cap and valve. 11. If removed, install pivot pin (3) and new nut (12) onto caliper, torque nut to 16 ft. lbs., then lubricate parking brake lever (5) and pivot pin. 12. Install pivot pin seal (1), parking brake lever and new sprag clip (2), ensuring teeth of sprag clip face away from lever, then snap seal cap over pivot pin. 13. Install the two collar return springs (26) onto retainer (31). Ensure retainer enters springs at end of second coil. 14. Install adjustment screw (11) into caliper housing until actuating collar is parallel to piston bore face of housing. 15. Lubricate guide pins with suitable grease, then slide boots onto pins. 16. Fill boots with grease, then install into mounting bracket. Ensure boots are properly positioned in grooves in pins and mounting bracket. 17. Install caliper and bleed brake system, then adjust parking brake free travel under Adjustments. Refer to Parking Brake System. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Fluid > Component Information > Technical Service Bulletins > Brake Fluid - Level & Filling Recommendations Brake Fluid: Technical Service Bulletins Brake Fluid - Level & Filling Recommendations File In Section: 05 - Brakes Bulletin No.: 00-05-22-004 Date: May, 2000 INFORMATION Subject: Brake Fluid Level and Filling Recommendations Models: 2001 and Prior Passenger Cars and Trucks Many dealers and after-market repair shops advertise multi-point fluid "top-ups" in conjunction with oil changes or regular maintenance packages. These offers often include adding brake fluid to the master cylinder reservoir. There are only two reasons why the brake fluid level in the brake reservoir might go down. The first is that the brake fluid level goes down an acceptable level during normal brake lining wear. When the linings are replaced, the fluid will return to it's original level. The second possible reason for a low fluid level is that fluid is leaking out of the brake system. If fluid is leaking, the brake system requires repair and adding additional fluid will not correct the leak. If the system was properly filled during delivery of the vehicle, no additional fluid should be required under most circumstances between brake pad and/or shoe replacements. This information can be reinforced with the customer by referring them to the Brake Fluid section of their vehicle's Owner's Manual. Guidelines GM vehicles have incorporated a variety of brake fluid reservoir styles. The following guidelines are restricted to the plastic bodied fluid reservoirs and do not affect the original service recommendations for the older style metal bodied units. You may encounter both black plastic and translucent style reservoirs. You may have reservoirs with: ^ A MAX fill mark only ^ A MIN fill mark only ^ Both MAX and MIN marks The translucent style reservoirs do not have to have the covers removed in order to view the fluid level. It is a good practice not to remove the reservoir cover unless necessary to reduce the possibility of contaminating the system. Use the following guidelines to assist in determining the proper fluid level. Important: When adding brake fluid, use Delco Supreme II(R) Brake Fluid, GM P/N 12377967 or equivalent brand bearing the DOT-3 rating only. Important: At no time should the fluid level be allowed to remain in an overfilled condition. Overfilling the brake reservoir may put unnecessary stress on the seals and cover of the reservoir. Use the following guidelines to properly maintain the fluid level. If the reservoir is overfilled, siphon out the additional fluid to comply with the guidelines below. Important: If under any circumstance the brake fluid level is extremely low in the reservoir or the BRAKE warning indicator is illuminated, the brake system should be checked for leaks and the system repaired in addition to bringing the fluid level up to the recommended guidelines outlined below. A leaking brake system will have reduced braking performance and will eventually not work at all. Important: Some vehicles have reservoirs that are very sensitive to brake fluid levels and may cause the BRAKE indicator to flicker on turns as the fluid approaches the minimum required level. If you encounter a vehicle with this concern, increase the fluid level staying within the guidelines outlined below. ^ If the reservoir has a MAX level indicator, the reservoir should be returned to the MAX marking only at the time new brake pads and/or shoes are installed. If the reservoir fluid level is at the half-way point or above do not attempt to add additional brake fluid during routine fluid checks. ^ If the reservoir has both MAX and MIN indicators, the fluid level should be maintained above the MIN indicator during routine fluid checks and returned to the MAX indication only after new brake pads and/or shoes are installed. ^ For reservoirs with only a MIN indication, the fluid level should be maintained above the MIN indicator during routine fluid checks. Return the Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Fluid > Component Information > Technical Service Bulletins > Brake Fluid - Level & Filling Recommendations > Page 6903 reservoir fluid level to full only after installing new brake pads and/or shoes. A full reservoir is indicated on translucent, snap cover reservoirs by a fluid level even with the top level of the view window imprinted into the side of the reservoir. On screw top models in black or translucent plastic, the full level is just below the bottom of the filler neck. Parts Information Part Number Description 12377967 Brake Fluid Parts are currently available from GMSPO. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Fluid > Component Information > Technical Service Bulletins > Page 6904 Brake Fluid: Specifications Brake System DOT 3 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Fluid Level Sensor/Switch > Component Information > Description and Operation Brake Fluid Level Sensor/Switch: Description and Operation OPERATION This sensor mounted on the master cylinder will activate the Brake Warning lamp if a low brake fluid level is detected. The lamp will turn off once the fluid level is corrected. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Fluid Pressure Sensor/Switch > Component Information > Locations LH Rear Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Fluid Pressure Sensor/Switch > Component Information > Locations > Page 6911 Brake Fluid Pressure Sensor/Switch: Description and Operation Fig. 3 Pressure Differential Valve & Brake Warning Lamp Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Fluid Pressure Sensor/Switch > Component Information > Locations > Page 6912 Fig. 4 Dual Master Cylinder W/Built In Warning Lamp Switch. DESCRIPTION In Fig. 3, as pressure falls in one system, the other system's normal pressure forces the piston to the inoperative side, contacting the switch terminal, causing the warning lamp on the instrument panel to glow. In Fig. 4 shows the switch mounted directly in the master cylinder assembly. Whenever there is a specified differential pressure, the switch piston will activate the brake failure warning switch and cause the brake warning lamp to glow. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Proportioning/Combination Valve > Component Information > Description and Operation > Brake Distribution Valve & Switch Brake Proportioning/Combination Valve: Description and Operation Brake Distribution Valve & Switch Fig. 12 Distribution Switch. Diagonally Split Brake System Fig. 16 Brake Distribution Switch. Normal Fig. 16 Brake Distribution Switch. Normal DESCRIPTION This switch assembly, Fig. 12. is used on some diagonally split brake systems and Corvette four wheel disc brake systems. It is connected to the outlet ports of the master cylinder and to the brake warning lamp and warns the driver if either the primary or secondary brake system has failed. OPERATION When hydraulic pressure is equal in both primary and secondary brake systems, the switch remains centered, Fig. 13. If pressure fails in one of the systems, the piston moves toward the inoperative side, Fig. 14. The shoulder of the piston contacts the switch terminal, providing a ground and lighting the warning lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Proportioning/Combination Valve > Component Information > Description and Operation > Brake Distribution Valve & Switch > Page 6917 Brake Proportioning/Combination Valve: Description and Operation Combination Valve Combination Valve Fig. 5 Combination Valve DESCRIPTION The combination valve, Fig. 5 is a metering valve, failure warning switch, and a proportioner in one assembly and is used on disc brake applications. OPERATION The metering valve delays front disc braking until the rear drum brake shoes contact the drum. The failure warning switch is actuated in event of front or rear brake system failure, in turn activating a dash warning lamp. The proportioner balances front to rear braking action during rapid deceleration. Metering Valve Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Proportioning/Combination Valve > Component Information > Description and Operation > Brake Distribution Valve & Switch > Page 6918 Fig. 6 Metering Valve. Initial Braking Fig. 7 Metering Valve. Continued Braking DESCRIPTION When the brakes are not applied, the metering valve permits the brake fluid to flow through the valve, thus allowing the fluid to expand and contract with temperature changes. OPERATION When the brakes are initially applied, the metering valve stem moves to the left, preventing fluid to flow through the valve to the front disc brakes. This is accomplished by the smooth end of the metering valve stem contacting the metering valve seal lip at 4 to 30 psi, Fig. 6. The metering valve spring holds the retainer against the seal until a predetermined pressure is produced at the valve inlet port which overcomes the spring pressure and permits hydraulic pressure to actuate the front disc brakes, Fig. 7. The increased pressure into the valve is metered through the valve seal, to the front disc brakes, producing an increased force on the diaphragm. The diaphragm then pulls the pin, in turn pulling the retainer and reduces the spring pressure on the metering valve seal. Eventually, the pressure reaches a point at which the spring is pulled away by the diaphragm pin and retainer, leaving the metering valve unrestricted, permitting full pressure to pass through the metering valve. Failure Warning Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Proportioning/Combination Valve > Component Information > Description and Operation > Brake Distribution Valve & Switch > Page 6919 Fig. 8 Failure Warning Switch. Rear System Failure DESCRIPTION If the rear brake system fails, the front system pressure forces the switch piston to the right, Fig. 8. The switch pin is then forced up into the switch, completing the electrical circuit and activates the dash warning lamp. OPERATION When repairs are made and pressure returns to the system, the piston moves to the left, resetting the switch. The detent on the piston requires approximately 100 to 450 psi to permit full reset of the piston. In event of front brake system failure, the piston moves to the left and the same sequence of events is followed as for rear system failure except the piston resets to the right. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Proportioning/Combination Valve > Component Information > Description and Operation > Brake Distribution Valve & Switch > Page 6920 Brake Proportioning/Combination Valve: Description and Operation Proportioning Valve Fig. 9 Proportioner. Rapid Deceleration Fig. 9 Proportioner. Rapid Deceleration Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Proportioning/Combination Valve > Component Information > Description and Operation > Brake Distribution Valve & Switch > Page 6921 Fig. 11 Proportioners Installed In Master Cylinder During rapid deceleration, a portion of vehicle weight is transferred to the front wheels. This resultant loss of weight at rear wheels must be compensated for to avoid early rear wheel skid. The proportioner or pressure control valve reduces rear brake system pressure, delaying rear wheel skid. When the proportioner or pressure control valve is incorporated in the combination valve assembly, pressure developed within the valve acts against the large end of the piston, overcoming the spring pressure, moving the piston left, Fig. 9. The piston then contacts the stem seat and restricts line pressure through the valve. During normal braking operation, the proportioner or pressure control valve is not functional. Brake fluid flows into the proportioner or pressure control valve between the piston center hole and the valve stem, through the stop plate and to the rear brakes. Spring pressure loads the piston during normal braking, causing it to rest against the stop plate, Fig. 10. On diagonally split brake systems, two proportioners or pressure control valves are used. One controls the left rear brake, the other the right rear brake. The proportioners or pressure control valves are installed in the master cylinder rear brake outlet ports, Fig. 11. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Locations > ABS Solenoid Valves Hydraulic Control Assembly - Antilock Brakes: Locations ABS Solenoid Valves The solenoid valves are located inside the hydraulic modulator are not serviceable. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Locations > ABS Solenoid Valves > Page 6926 Hydraulic Control Assembly - Antilock Brakes: Locations Brake Pressure Modulator The hydraulic modulator (also known as Brake Pressure Modulator (BPM) or Pressure Modulator Valve (PMV)) is located on the front lefthand side of the engine compartment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Locations > ABS Solenoid Valves > Page 6927 Brake Pressure Modulator Valve (With Electronic Brake Control Module) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Locations > Page 6928 Hydraulic Control Assembly - Antilock Brakes: Diagrams Brake Pressure Modulator Valve (BPMV) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Locations > Page 6929 Brake Pressure Modulator Valve (BPMV) (With Electronic Brake Control Module (EBCM)) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Description and Operation > ABS Solenoid Valves Hydraulic Control Assembly - Antilock Brakes: Description and Operation ABS Solenoid Valves DESCRIPTION The solenoid valves are located inside the hydraulic modulator are not serviceable. The solenoid valves increase, decrease or maintain the brake fluid pressure to the wheel circuits. During anti-lock braking the valves are controlled by signals received by the EBCM/EBTCM. During normal braking, the valves are positioned in a pressure increase or open position. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Description and Operation > ABS Solenoid Valves > Page 6932 Hydraulic Control Assembly - Antilock Brakes: Description and Operation Hydraulic Modulator Valve DESCRIPTION The hydraulic modulator (also known as Brake Pressure Modulator (BPM) or Pressure Modulator Valve (PMV)) is located on the front lefthand side of the engine compartment, provides brake fluid modulation for each individual wheel circuit as required during anti-lock braking. During anti-lock braking, the modulator can maintain or reduce brake fluid pressure independent of the pressure generated in the master cylinder. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Hydraulic Control Assembly Antilock Brakes > Component Information > Description and Operation > Page 6933 Hydraulic Control Assembly - Antilock Brakes: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Disconnect and remove air intake duct and resonator, then position upper coolant hose aside. 3. Disconnect canister purge line at canister and position aside. 4. Remove modulator valve cover attaching screw and cover. 5. Disconnect modulator valve electrical connector and ground wire. 6. Disconnect all hydraulic lines to modulator valve, then plug pipes to prevent loss of fluid and fluid contamination. Note location of pipes for installation reference. 7. Remove three modulator valve to bracket attaching nuts, then the modulator valve from vehicle. 8. Reverse procedure to install, then perform ABS system check as described in System Diagnosis. See: Antilock Brakes / Traction Control Systems/Testing and Inspection NOTE: Ensure brake hydraulic pipes are installed correctly. Pipes that are crossed during installation could cause wheel lock-up. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Master Cylinder > Component Information > Specifications Brake Master Cylinder: Specifications Master Cylinder Bore Dia., Inch ........................................................................................................... ........................................................................ 1.125 Front Caliper Bore Dia., Inch ............................ ............................................................................................................................................................ 2.952 Wheel Cylinder Bore Dia., Inch ................................................................................................. .......................................................................................... 1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Master Cylinder > Component Information > Service and Repair > Master Cylinder Disassembly/Assembly Brake Master Cylinder: Service and Repair Master Cylinder Disassembly/Assembly Dual Master Cylinder Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Master Cylinder > Component Information > Service and Repair > Master Cylinder Disassembly/Assembly > Page 6939 Compact Master Cylinder Assembly Master Cylinder Reservoir Removal. Composite Type Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Master Cylinder > Component Information > Service and Repair > Master Cylinder Disassembly/Assembly > Page 6940 DISASSEMBLE Refer to Figs. 19 and 20 when performing the following procedures. 1. Remove master cylinder from vehicle as follows: a. Disconnect and plug hydraulic lines. b. Remove two master cylinder attaching nuts, then the master cylinder. 2. Remove reservoir cover and diaphragm. Discard old brake fluid in reservoir. 3. Inspect cover and diaphragm. Replace if cut, cracked or deformed. 4. Remove fluid level switch, if equipped. 5. On models with compact master cylinder, remove proportioner valve assembly, Fig. 20. 6. On all models, depress primary piston and remove lock ring. 7. Plug primary fluid outlet (outlet nearest to cowl when master cylinder is installed), then apply compressed air into secondary fluid outlet to remove primary and secondary pistons. 8. Remove spring retainer and seals from secondary piston. 9. Clamp master cylinder in a vise as shown in Fig. 21, then remove reservoir using a pry bar. Remove reservoir grommets. 10. Inspect master cylinder bore for corrosion. Do not use abrasive material on master cylinder bore. Replace if bore is corroded. ASSEMBLE Clean all parts not included in repair kit with brake fluid. Do not dry with compressed air. Lubricate all rubber parts with clean brake fluid prior to installation. 1. Lubricate new reservoir grommets with silicone brake lube, then press grommets into master cylinder body. Ensure grommets are properly seated. 2. Lay reservoir upside down on flat, hard surface. Press master cylinder body onto reservoir using rocking motion. 3. Install new seals on secondary piston, then the spring retainer. 4. Install spring and secondary piston assembly into cylinder. 5. Install primary piston. Depress primary piston into cylinder, then install lock ring. 6. Install fluid level switch, if equipped. 7. On models with compact master cylinder, install proportioner valve assembly, Fig. 20. 8. On all models, fit diaphragm into reservoir cover, then install cover onto reservoir. 9. Install master cylinder and bleed brake system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Brake Master Cylinder > Component Information > Service and Repair > Master Cylinder Disassembly/Assembly > Page 6941 Brake Master Cylinder: Service and Repair Master Cylinder Replace 1. Disconnect wire connector from brake warning pressure switch, if equipped. 2. Disconnect brake lines from master cylinder. 3. Remove master cylinder mounting nuts, then the master cylinder. 4. On models with separate fluid reservoirs, remove reservoir. 5. On all models, reverse procedure to install, noting the following: a. Refer to Master Cylinder Push Rod for procedures on push rod adjustments. b. Bleed brakes as described under Brake Bleeding. Refer to Brakes/Service and Repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Wheel Cylinder > Component Information > Technical Service Bulletins > Brakes - Wheel Cylinder Inspection Guidelines Wheel Cylinder: Technical Service Bulletins Brakes - Wheel Cylinder Inspection Guidelines Bulletin No.: 03-05-24-001A Date: March 21, 2005 INFORMATION Subject: Service Information Regarding Rear Brake Drum Wheel Cylinder Inspections Models: 2005 and Prior GM Passenger Cars and Trucks 2005 and Prior Saturn Vehicles with Rear Drum Brakes Supercede: This bulletin is being revised add model years and include all GM vehicles. Please discard Corporate Bulletin Number 03-05-24-001 (Section 03 - Suspension). This bulletin provides information on proper inspection of rear drum brake wheel cylinders. Important: It is not recommended that dust boots be removed during inspection processes as dirt and debris could contaminate the wheel cylinder bore causing premature wear of the wheel cylinder. In addition, most bores should look damp and some lubricant may drip out from under the boot as a result of lubricant being present. All rear drum brake wheel cylinders are assembled with a lubricant to aid in assembly, provide an anti-corrosion coating to the cylinder bore, and lubricate internal rubber components. As a result of this lubrication process, it is not uncommon for some amount of lubricant to accumulate at the ends of the cylinder under the dust boot. Over time, the lubricant may work its way to the outside of the boot and cause an area of the boot to look damp. Evidence of a damp area on the boot does not indicate a leak in the cylinder. However, if there is excessive wetness (i.e. drips) coming from the boot area of the wheel cylinder, it could indicate a brake hydraulic fluid leak requiring wheel cylinder replacement. (Refer to the Wheel Cylinder Replacement procedures in the appropriate Service Manual.) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Wheel Cylinder > Component Information > Technical Service Bulletins > Page 6946 Wheel Cylinder: Specifications Wheel Cylinder Bore Diameter 1 in Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Hydraulic System, Brakes > Wheel Cylinder > Component Information > Technical Service Bulletins > Page 6947 Wheel Cylinder: Service and Repair Fig. 33 Exploded View Of Wheel Cylinder 1. Raise and support vehicle. 2. Remove wheel, drum and brake shoes. 3. Disconnect hydraulic line at wheel cylinder. Do not pull metal line away from cylinder, as this may kink or bend line. Line will separate from cylinder when cylinder is moved away from brake backing plate. 4. Remove wheel cylinder-to-brake plate attaching screws, then the wheel cylinder. 5. Remove boots, pistons, springs and cups from cylinder, Fig. 33. 6. Clean all parts with brake fluid. 7. Inspect cylinder bore. A scored bore may be honed as long as the diameter is not increased by more than .005 inch. Replace worn or damaged parts as necessary. 8. Ensure hands are clean before proceeding with assembly. Lubricate cylinder wall and rubber cups with brake fluid, then install springs, cups, pistons and boots in housing. 9. Wipe end of hydraulic line to remove any foreign matter, then place wheel cylinder in position. Enter tubing into cylinder and start threads on fitting. 10. Secure cylinder to backing plate, then complete tightening of tubing fitting. 11. Install brake shoes, drum and wheel. 12. Bleed system as outlined previously, then adjust brakes. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Parking Brake System > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Parking Brake System > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch > Page 6953 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Description and Operation > Power Brake Unit Vacuum Brake Booster: Description and Operation Power Brake Unit Fig. 1 Exploded View Of AC-Delco Tandem Diaphragm Booster Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Description and Operation > Power Brake Unit > Page 6959 Fig. 2 Exploded View Of Power Head Assembly. AC-Delco Tandem Diaphragm Booster DESCRIPTION This unit utilizes a vacuum power chamber, consisting of a front and rear shell, housing divider, front and rear diaphragm, plate assemblies, hydraulic pushrod and a diaphragm return spring, Fig. 1 and 2 . OPERATION In normal operating mode, with service brakes in released position, the booster operates with vacuum on both sides of its diaphragms. When brakes are applied, air at atmospheric pressure is admitted to one side of each diaphragm to provide power assist. When the service brake is released, atmospheric air is shut off from one side of each diaphragm. The air is then drawn from the booster through the vacuum check valve to the vacuum source. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Description and Operation > Power Brake Unit > Page 6960 Vacuum Brake Booster: Description and Operation General Service Two basic types of power assist mechanisms are used: vacuum assist diaphragm assemblies, which use engine vacuum or, in some cases vacuum pressure developed by an external vacuum pump. The second type is a hydraulic pressure assist mechanism, which use pressure developed by an external pump (usually the power steering pump). Both systems act to increase the force exerted on the master cylinder piston by the operator. This in turn increases the hydraulic pressure delivered to the wheel cylinders, while decreasing driver effort necessary to obtain acceptable stopping performance. Vacuum assist units are similar in operation and get their energy by opposing engine vacuum to atmospheric pressure. A piston and cylinder, flexible diaphragm (bellows) utilize this energy to provide brake assistance. The fundamental difference between these types of vacuum assist systems lies simply in how the diaphragm within the power unit is suspended when the brakes are not applied. In order to properly diagnose vacuum assist system malfunctions it is important to know whether the diaphragm within a power unit is air suspended or vacuum suspended. Air-suspended units are under atmospheric pressure until the brakes are applied. Engine vacuum is then admitted, causing the piston or diaphragm to move (or the bellows to collapse). Vacuum-suspended types are balanced with engine vacuum until the brake pedal is depressed, allowing atmospheric pressure to unbalance the unit and apply force to the brake system. Regardless of whether the brakes are vacuum or hydraulically assisted, certain general service procedures apply. Only specified, clean brake fluid should be used in brake system. On hydro-boost systems, use of the specified hydraulic fluid in the boost circuit is essential to proper system operation. Care must be taken not to mix the fluids of the two separate operating circuits. Use of improper fluids, or contaminated fluid will cause damage to the seals and valves. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Testing and Inspection > Brakes Grab Vacuum Brake Booster: Testing and Inspection Brakes Grab 1. Faulty control valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Testing and Inspection > Brakes Grab > Page 6963 Vacuum Brake Booster: Testing and Inspection Hard Pedal 1. Internal vacuum leak. 2. Faulty control valve. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Testing and Inspection > Brakes Grab > Page 6964 Vacuum Brake Booster: Testing and Inspection Slow or No Release 1. Faulty pushrod adjustment. 2. Bind in linkage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Adjustments > Gauge Method Vacuum Brake Booster: Adjustments Gauge Method Fig. 7 Master Cylinder Pushrod Adjustment. AC-Delco Type Vacuum Booster On these models, the master cylinder pushrod length is fixed and is usually only checked after the unit has been overhauled. 1. Assemble booster unit and install pushrod, ensuring pushrod is fully seated. 2. Position go/no go gauge furnished in repair kit over pushrod as shown in Fig. 7 3. If pushrod height is not within limits of gauge, install service adjustable pushrod and adjust rod to obtain correct height. 4. Install power unit and check adjustment, ensuring master cylinder compensating port is open with engine running and brake pedal released. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Adjustments > Gauge Method > Page 6967 Vacuum Brake Booster: Adjustments Air Method 1. Be sure master cylinder attaching nuts are tight. 2. Remove master cylinder filler cap. 3. With brake released, force compressed air into the hydraulic outlet of the master cylinder. Regulate air pressure to a value of approximately 5 psi, to prevent spraying brake fluid from master cylinder. Care must be taken not to allow brake fluid to contact painted surfaces of vehicle, skin or eyes, as damage or personal injury will result. 4. If air passes through the compensating port, which is the smaller of the two holes in the bottom of the master cylinder reservoir, the adjustment is satisfactory. 5. If air does not flow through the compensating port, adjust the pushrod as required, either by means of the adjustment screw (if provided) or by adding shims between the master cylinder and power unit shell until the air flows freely. 6. Reconnect brake lines and bleed system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Power Brake Assist > Vacuum Brake Booster > Component Information > Adjustments > Page 6968 Vacuum Brake Booster: Service and Repair The tandem diaphragm type power brake booster is no longer serviceable and should be replaced as an assembly, Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Relays and Modules - Brakes and Traction Control > ABS Main Relay > Component Information > Service and Repair ABS Main Relay: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Remove ABS modulator protective cover. 3. Remove relay from modulator. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations Brake Pressure Modulator Valve (With Electronic Brake Control Module) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations > Page 6976 Brake Pressure Modulator Valve (BPMV) (With Electronic Brake Control Module (EBCM)) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations > Page 6977 Electronic Brake Control Module: Description and Operation DESCRIPTION The EBCM is a small control computer located under the trim panel on the lefthand side of the passenger compartment on wagon models, and on the lefthand side of the luggage compartment on sedan models. This computer monitors the speed of each wheel and the electrical status of the hydraulic modulator. The primary functions of EBCM are to detect wheel locking, control the brake function while in anti-lock mode and monitor system for correct electrical operation. The EBCM also controls the display of the ABS diagnostic trouble codes. If the EBCM detects a fault, it can disable the ABS system and activate the ABS warning lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Relays and Modules - Brakes and Traction Control > Electronic Brake Control Module > Component Information > Locations > Page 6978 Electronic Brake Control Module: Service and Repair REPLACEMENT 1. Disconnect battery ground cable. 2. Disconnect EBCM electrical connector. 3. Remove two EBCM to bracket attaching nuts, then the EBCM from the vehicle. 4. Reverse procedure to install, perform ABS system check as described in System Diagnosis. See: Antilock Brakes / Traction Control Systems/Testing and Inspection Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Brake Fluid Level Sensor/Switch > Component Information > Description and Operation Brake Fluid Level Sensor/Switch: Description and Operation OPERATION This sensor mounted on the master cylinder will activate the Brake Warning lamp if a low brake fluid level is detected. The lamp will turn off once the fluid level is corrected. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Brake Fluid Pressure Sensor/Switch > Component Information > Locations LH Rear Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Brake Fluid Pressure Sensor/Switch > Component Information > Locations > Page 6986 Brake Fluid Pressure Sensor/Switch: Description and Operation Fig. 3 Pressure Differential Valve & Brake Warning Lamp Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Brake Fluid Pressure Sensor/Switch > Component Information > Locations > Page 6987 Fig. 4 Dual Master Cylinder W/Built In Warning Lamp Switch. DESCRIPTION In Fig. 3, as pressure falls in one system, the other system's normal pressure forces the piston to the inoperative side, contacting the switch terminal, causing the warning lamp on the instrument panel to glow. In Fig. 4 shows the switch mounted directly in the master cylinder assembly. Whenever there is a specified differential pressure, the switch piston will activate the brake failure warning switch and cause the brake warning lamp to glow. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch > Page 6992 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front Wheel Speed Sensor: Locations Wheel Speed Sensor Lead, Front LH Rear Engine Compartment LH Front Frame Rail RH Front Frame Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 6997 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 6998 Wheel Speed Sensor: Locations Wheel Speed Sensor, Rear LH Rear Frame Rail (Without Automatic Level Control) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Wheel Speed Sensor Lead, Front > Page 6999 Antilock Brake System Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Locations > Page 7000 Wheel Speed Sensor: Description and Operation DESCRIPTION These sensors transmit wheel speed information to the EBCM using a small amount of AC voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor Wheel Speed Sensor: Service and Repair Left Front Wheel Speed Sensor REPLACEMENT 1. Raise and support vehicle. 2. Disconnect wheel speed sensor harness connector and sensor assembly connector from clip. 3. Disconnect speed sensor connector from harness connector. 4. Remove sensor bracket attaching bolt from frame rail. 5. Disconnect wheel speed sensor assembly harness with grommets from brackets and combination valve brake pipe clip. Note position of grommets and harness for installation reference. 6. Remove speed sensor retaining bolt, then the speed sensor from steering knuckle. 7. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the knuckle and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor > Page 7003 Wheel Speed Sensor: Service and Repair Rear Axle Speed Sensor 1. Raise and support vehicle. 2. Unclip sensor assembly connector and differential sensor connector, then separate the connectors. 3. Disconnect speed sensor harness assembly wiring harness with gromments from sensor bracket. Note position of grommets and harness for installation reference. 4. Remove sensor attaching bolt, then the sensor from the vehicle. 5. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the axle housing and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Brakes and Traction Control > Sensors and Switches - Brakes and Traction Control > Wheel Speed Sensor > Component Information > Service and Repair > Left Front Wheel Speed Sensor > Page 7004 Wheel Speed Sensor: Service and Repair Right Front Wheel Speed Sensor REPLACEMENT 1. Disconnect forward lamp harness wheel speed sensor connector and wheel speed sensor assembly connector from clip. 2. Disconnect forward lamp harness connector from wheel speed sensor connector. 3. Raise and support vehicle. 4. Remove sensor bracket attaching bolt from frame rail. 5. Remove sensor assembly harness with grommets from brackets. Note position of grommets and harness for assembly reference. 6. Remove sensor retaining bolt, then the sensor from vehicle. 7. Reverse procedure to install. CAUTION: The wheel speed sensors are a tight fit into the knuckle and are to be pushed in by hand. Do not hammer sensor into position. Proper installation of sensor assembly wire into the bracket is critical. Failure to install wire on bracket could cause wire to come in contact with moving parts, causing circuit damage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions Neutral Safety Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7011 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7012 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7013 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7014 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7015 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7016 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7017 Neutral Safety Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7018 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7019 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7020 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7021 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7022 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7023 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7024 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7025 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7026 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7027 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7028 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7029 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7030 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7031 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7032 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7033 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7034 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7035 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7036 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7037 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7038 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7039 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7040 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7041 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Page 7042 Neutral Safety Switch: Service and Repair Fig. 4 Mechanical Neutral Safety System. Tilt Column Fig. 5 Mechanical Neutral Safety System. Standard Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Sensors and Switches - Starting and Charging > Neutral Safety Switch > Component Information > Diagrams > Page 7043 Fig. 6 Mechanical Neutral Safety System In Park Position MECHANICAL Actuation of the ignition switch is prevented by a mechanical lockout system Fig. 4 AND 5,. which prevents the lock cylinder from rotating when the selector lever is out of Park or Neutral. When the selector lever is in Park or Neutral, the slots in the bowl plate and the finger on the actuator rod align, allowing the finger to pass through the bowl plate in turn actuating the ignition switch, Fig. 6. If the selector lever is in any position other than Park or Neutral, the finger contacts the bowl plate when the lock cylinder is rotated, thereby preventing full travel of the lock cylinder. ELECTRIC On models incorporating an electric neutral start switch, the start switch, back-up light switch and parking brake vacuum release valve are combined into one unit. This unit is mounted on the steering column under the instrument panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Battery > Battery Cable > Positive, Battery Cable > System Information > Locations Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Technical Service Bulletins > Tools - Released for CS Generator Diagnosis Alternator: Technical Service Bulletins Tools - Released for CS Generator Diagnosis File In Section: 6 - Engine Bulletin No.: 83-64-09 Date: March, 1998 INFORMATION Subject: New Tool J 41450-B, Released for CS Generator Diagnosis Models: 1988-98 Passenger Cars and Light Trucks with CS-Series Generators A new CS-Series Generator Tester, J 41450-B, has been sent to all dealers as part of the Essential Tool Package. This tool will work on all CS-Series generators for past model years. The tool is shown in Figure 1. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Technical Service Bulletins > Tools - Released for CS Generator Diagnosis > Page 7054 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Technical Service Bulletins > Tools - Released for CS Generator Diagnosis > Page 7055 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Technical Service Bulletins > Tools - Released for CS Generator Diagnosis > Page 7056 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Technical Service Bulletins > Tools - Released for CS Generator Diagnosis > Page 7057 Generator Not Operating Properly The charts shown can be used in place of the diagnostic procedures in previous Service Manuals when this new tool is used. This information will be included in the 1999 Service Manual. Inspect the following before testing the generator: ^ The battery. Make sure the vehicle battery is in good condition and fully charged. Refer to Battery Load Test. ^ The built in hydrometer in the battery. The green eye must be showing in the hydrometer. ^ The voltage across the battery terminals with all the loads OFF should be above 12 V. Refer to Battery Load Test. ^ Make sure the battery connections are clean and tight. ^ The drive belt for damage or looseness. ^ The wiring harness at the generator. Make sure the harness connector is tight and latched. Make sure the output terminal of the generator is connected to the vehicle battery (positive) generator lead. ^ All the charging system related fuses and electrical connections for damage or looseness. Refer to the starter and charging system schematics. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Technical Service Bulletins > Page 7058 Alternator: Specifications Alternator Model [06] ........................................................................................................................... ..................................................................... CS-130 Rated Hot Output Amps ................................... .............................................................................................................................................................. .. 100 [06] Service part identification code K60 (100 amp. alternator). Refer to the service parts identification label located on the deck lid or the spare tire cover. Alternator Model [07] ........................................................................................................................... ..................................................................... CS-130 Rated Hot Output Amps ................................... .............................................................................................................................................................. .. 105 [07] Service part identification code K68 (105 amp. alternator). Refer to the service parts identification label located on the deck lid or the spare tire cover. Alternator Model [01] ........................................................................................................................... ..................................................................... CS-144 Rated Hot Output Amps ................................... .............................................................................................................................................................. .. 124 [01] Except part identification code KG9. Alternator Model [02] ........................................................................................................................... ..................................................................... CS-144 Rated Hot Output Amps ................................... .............................................................................................................................................................. .. 140 [02] Service part identification code KG9 (140 amp. alternator). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Technical Service Bulletins > Page 7059 Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions Alternator: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7062 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7063 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7064 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7065 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7066 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7067 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7068 Alternator: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7069 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7070 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7071 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7072 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7073 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7074 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7075 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7076 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7077 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7078 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7079 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7080 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7081 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7082 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7083 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7084 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7085 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7086 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7087 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7088 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7089 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7090 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7091 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7092 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Diagram Information and Instructions > Page 7093 Generator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Page 7094 Alternator: Service Precautions 1. Be certain that battery polarity is correct when servicing units. Reversed battery polarity will damage rectifiers and regulators. 2. If booster battery is used for starting, be sure to use correct polarity in hook up. 3. When a fast charger is used to charge a vehicle battery, the vehicle battery cables should be disconnected unless the fast charger is equipped with a special Alternator Protector, in which case the vehicle battery cables need not be disconnected. Also the fast charger should never be used to start a vehicle as damage to rectifiers will result. 4. Unless the system includes a load relay or field relay, grounding the alternator output terminal will damage the alternator and/or circuits. This is true even when the system is not in operation since no circuit breaker is used and the battery is applied to the alternator output terminal at all times. The field or load relay acts as a circuit breaker in that it is controlled by the ignition switch. 5. Before making any on vehicle tests of the alternator or regulator, the battery should be checked and the circuit inspected for faulty wiring or insulation. loose or corroded connections and poor ground circuits. 6. Check alternator belt tension to be sure the belt is tight enough to prevent slipping under load. 7. The ignition switch should be off and the battery ground cable disconnected before making any test connections to prevent damage to the system. 8. The vehicle battery must be fully charged or a fully charged battery may be installed for test purposes. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Page 7095 Alternator: Description and Operation Fig. 1 Exploded View Of CS Type Alternator Rotor Drive End Fig. 2 Exploded View Of CS Type Alternator Slip Ring End Components Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Charging System > Alternator > Component Information > Diagrams > Page 7096 DESCRIPTION The CS alternator is available in three sizes: CS-121, CS-130, CS-130D and CS-144. The numerals denote the outer diameter of the stator laminations in millimeters and the letters CS stand for charging system. The CS-144 can be serviced. The CS-121 and CS-130 series are serviced as an assembly only. The CS alternators, Fig. 1 and 2 , use a new type regulator and a diode trio is not used. A delta stator, rectifier bridge, and rotor with slip rings and brushes are electrically similar to earlier alternators. A conventional fan mounted next to the pulley pulls air through the assembly for cooling. An internal fan mounted on the rotor pulls air through the slip ring end frame to cool rectifier, bridge and regulator. Air is expelled through openings in the end frame. No periodic maintenance is required. OPERATION CS-130 and CS-144 alternators may be used with only two connections. The battery positive BAT terminal must be connected to a battery during operation. The second required connection is through the indicator light, or a suitable external resistor to L terminal of the regulator which serves to turn unit On at start up. Three other regulator terminals are available for optional use in vehicle systems. The P terminal is connected to the stator, and may be connected to a tachometer or other device. The F terminal is connected internally to field positive, and may be used as a fault indicator. The S terminal may be connected externally to a voltage, such as battery voltage, to sense voltage to be controlled. The regulator voltage setting varies with temperature, and limits system voltage by controlling rotor field current. Unlike others regulators, this regulator switches field current On and Off at a fixed frequency about 400 cycles per second. By varying On-Off time, correct average field current is obtained to provide proper system voltage. At high speeds, the On time may be 10% and Off time 90%. At low speeds with high electrical loads, On-Off time may be 90% and 10% respectively. Alternator systems on some applications are controlled by a Body Control Module (BCM). If cause of a system malfunction cannot be determined using the following test procedure, a problem in the electronic control system is indicated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information Key: Technical Service Bulletins Locks - Key Code Security Rules and Information INFORMATION Bulletin No.: 10-00-89-010 Date: May 27, 2010 Subject: Key Code Security Rules and Information on GM KeyCode Look-Up Application (Canada Only) Models: 2011 and Prior GM Passenger Cars and Trucks 2010 and Prior HUMMER H2, H3 2009 and Prior Saturn and Saab 2002 and Prior Isuzu Attention: This bulletin has been created to address potential issues and questions regarding KeyCode security. This bulletin should be read by all parties involved in KeyCode activity, including dealer operator, partner security coordinator, sales, service and parts departments. A copy of this bulletin should be printed and maintained in the parts department for use as a reference. Important U.S. dealers should refer to Corporate Bulletin Number 10-00-89-009. Where Are Key Codes Located? General Motors provides access to KeyCodes through three sources when a vehicle is delivered to a dealer. Vehicle KeyCodes are located on the original vehicle invoice to the dealership. There is a small white bar coded tag sent with most new vehicles that also has the key code printed on it. Dealerships should make a practice of comparing the tag's keycode numbers to the keycode listed on the invoice. Any discrepancy should be reported immediately to the GM of Canada Key Code Inquiry Desk. Remember to remove the key tag prior to showing vehicles to potential customers. The third source for Key codes is through the GM KeyCode Look-Up feature within the OEConnection D2DLink application. KeyCode Look-Up currently goes back 17 previous model years from the current model year. When a vehicle is received by the dealership, care should be taken to safeguard the original vehicle invoice and KeyCode tag provided with the vehicle. Potential customers should not have access to the invoice or this KeyCode tag prior to the sale being completed. After a sale has been completed, the KeyCode information belongs to the customer and General Motors. Tip Only the original invoice contains key code information, a re-printed invoice does not. GM KeyCode Look-Up Application for GM of Canada Dealers All dealers should review the General Motors of Canada KeyCode Look-Up Policies and Procedures (Service Policy & Procedures Manual Section 3.1.6 "Replacement of VIN plates & keys"). Please note that the KeyCode Access site is restricted. Only authorized users should be using this application. Please see your Parts Manager for site authorized users. KeyCode Look-Up currently goes back 17 years from current model year. Important notes about security: - Users may not access the system from multiple computers simultaneously. - Users may only request one KeyCode at a time. - KeyCode information will only be available on the screen for 2 minutes. - Each user is personally responsible for maintaining and protecting their password. - Never share your password with others. - User Id's are suspended after 6 consecutive failed attempts. - User Id's are disabled if not used for 90 days. - Processes must be in place for regular dealership reviews. - The Parts Manager (or assigned management) must have processes in place for employee termination or life change events. Upon termination individuals access must be turned off immediately and access should be re-evaluated upon any position changes within the dealership. - If you think your password or ID security has been breached, contact Dealer Systems Support at 1-800-265-0573. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information > Page 7102 Each user will be required to accept the following agreement each time the KeyCode application is used. Key Code User Agreement - Key codes are proprietary information belonging to General Motors Corporation and to the vehicle owner. - Unauthorized access to, or use of, key code information is unlawful and may subject the user to criminal and civil penalties. - This information should be treated as strictly confidential and should not be disclosed to anyone unless authorized. I will ensure that the following information is obtained prior to releasing any Key Code information: 1. Government issued picture ID (Drivers License) 2. Registration or other proof of ownership. Registration should have normal markings from the Province that issued the registration and possibly the receipt for payment recorded as well. Important - GM takes this agreement seriously. Each user must be certain of vehicle ownership before giving out key codes. - When the ownership of the vehicle is in doubt, dealership personnel should not provide the information. Key code requests should never be received via a fax or the internet and key codes should never be provided to anyone in this manner. A face to face contact with the owner of the vehicle is the expected manner that dealers will use to release a key code or as otherwise stipulated in this bulletin or other materials. - Key codes should NEVER be sent via a fax or the internet. - Each Dealership should create a permanent file to document all KeyCode Look Up transactions. Requests should be filed by VIN and in each folder retain copies of the following: - Government issued picture ID (Drivers License) - Registration or other proof of ownership. - Copy of the paid customer receipt which has the name of the employee who cut and sold the key to the customer. - Do not put yourself or your Dealership in the position of needing to "explain" a KeyCode Look Up to either GM or law enforcement officials. - Dealership Management has the ability to review all KeyCode Look-Up transactions. - Dealership KeyCode documentation must be retained for two years. Frequently Asked Questions (FAQs) for GM of Canada Dealers How do I request a KeyCode for customer owned vehicle that is not registered? Scrapped, salvaged or stored vehicles that do not have a current registration should still have the ownership verified by requesting the vehicle title, current insurance policy and / or current lien holder information from the customers financing source. If you cannot determine if the customer is the owner of the vehicle, do not provide the key code information. In these cases, a short description of the vehicle (scrapped, salvaged, etc.) and the dealership location should be kept on file. Any clarifying explanation should be entered into the comments field. How do I document a KeyCode request for a vehicle that is being repossessed? The repossessor must document ownership of the vehicle by providing a court ordered repossession order and lien-holder documents prior to providing key code information. Copies of the repossessors Drivers License and a business card should be retained by the dealership for documentation. What do I do if the registration information is locked in the vehicle? Every effort should be made to obtain complete information for each request. Each Dealership will have to decide on a case by case basis if enough information is available to verify the customer's ownership of the vehicle. Other forms of documentation include vehicle title, insurance policy, and or current lien information from the customers financing source. Dealership Management must be involved in any request without complete information. If you cannot determine if the customer is the owner of the vehicle, do not provide the key code information. Can I get a print out of the information on the screen? It is important to note that the Key Code Look Up Search Results contain sensitive and/or proprietary information. For this reason GM recommends against printing it. If the Search Results must be printed, store and/or dispose of the printed copy properly to minimize the risk of improper or illegal use. Who in the dealership has access to the KeyCode application? Dealership Parts Manager (or assigned management) will determine, and control, who is authorized to access the KeyCode Look Up application. However, we anticipate that dealership parts and service management will be the primary users of the application. The KeyCode Look Up application automatically tracks each user activity session. Information tracked by the system includes: User name, User ID, all other entered data and the date/time of access. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information > Page 7103 What if I input the VIN incorrectly? If an incorrect VIN is entered into the system (meaning that the system does not recognize the VIN or that the VIN has been entered incorrectly) the system will return an error message. If I am an authorized user for the KeyCode application, can I access the application from home? Yes. What if I suspect key code misuse? Your dealership should communicate the proper procedures for requesting key codes. Any suspicious activity either within the dealership or externally should be reported to Dealer Systems Support at 1-800-265-0573 or GM of Canada Key Code Inquiry Desk at 1-905-644-4892. Whose key codes can I access through the system? At this time the following Canadian vehicle codes are available through the system: Chevrolet, Cadillac, Buick, Pontiac, GMC, HUMMER (H2 and H3 only), Oldsmobile, Saturn, Saab and Isuzu (up to 2002 model year) for a maximum of 17 model years. What should I do if I enter a valid VIN and the system does not produce any key code information? Occasionally, the KeyCode Look Up application may not produce a key code for a valid VIN. This may be the result of new vehicle information not yet available. In addition, older vehicle information may have been sent to an archive status. If you do not receive a key code returned for valid VIN, you should contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. How do I access KeyCodes if the KeyCode Look-up system is down? If the KeyCode Look-up system is temporarily unavailable, you can contact the original selling dealer who may have it on file or contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. If the customer is dealing with an emergency lock-out situation, you need to have the customer contact Roadside assistance, OnStar if subscribed, or 911. What should I do if the KeyCode from the look-up system does not work on the vehicle? On occasion a dealer may encounter a KeyCode that will not work on the vehicle in question. In cases where the KeyCode won't work you will need to verify with the manufacturer of the cutting equipment that the key has been cut correctly. If the key has been cut correctly you may be able to verify the proper KeyCode was given through the original selling dealer. When unable to verify the KeyCode through the original selling dealer contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. If the key has been cut correctly and the code given does not work, the lock cylinder may have been changed. In these situations following the proper SI document for recoding a key or replacing the lock cylinder may be necessary. How long do I have to keep KeyCode Records? Dealership KeyCode documentation must be retained for two years. Can I get a KeyCode changed in the Look-Up system? Yes, KeyCodes can be changed in the Look-Up system if a lock cylinder has been changed. Contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. What information do I need before I can provide a driver of a company fleet vehicle Keys or KeyCode information? The dealership should have a copy of the individual's driver's license, proof of employment and registration. If there is any question as to the customer's employment by the fleet company, the dealer should attempt to contact the fleet company for verification. If there is not enough information to determine ownership and employment, this information should not be provided. How do I document a request from an Independent Repair facility for a KeyCode or Key? The independent must provide a copy of their driver's license, proof of employment and signed copy of the repair order for that repair facility. The repair order must include customer's name, address, VIN, city, province and license plate number. Copies of this information must be included in your dealer KeyCode file. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information > Page 7104 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions Neutral Safety Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7109 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7110 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7111 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7112 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7113 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7114 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7115 Neutral Safety Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7116 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7117 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7118 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7119 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7120 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7121 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7122 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7123 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7124 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7125 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7126 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7127 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7128 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7129 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7130 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7131 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7132 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7133 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7134 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7135 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7136 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7137 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7138 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7139 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Page 7140 Neutral Safety Switch: Service and Repair Fig. 4 Mechanical Neutral Safety System. Tilt Column Fig. 5 Mechanical Neutral Safety System. Standard Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Neutral Safety Switch > Component Information > Diagrams > Page 7141 Fig. 6 Mechanical Neutral Safety System In Park Position MECHANICAL Actuation of the ignition switch is prevented by a mechanical lockout system Fig. 4 AND 5,. which prevents the lock cylinder from rotating when the selector lever is out of Park or Neutral. When the selector lever is in Park or Neutral, the slots in the bowl plate and the finger on the actuator rod align, allowing the finger to pass through the bowl plate in turn actuating the ignition switch, Fig. 6. If the selector lever is in any position other than Park or Neutral, the finger contacts the bowl plate when the lock cylinder is rotated, thereby preventing full travel of the lock cylinder. ELECTRIC On models incorporating an electric neutral start switch, the start switch, back-up light switch and parking brake vacuum release valve are combined into one unit. This unit is mounted on the steering column under the instrument panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Motor > Starter Drive/Bendix > Component Information > Testing and Inspection > Drive Clutch Failure - A/C Delco Starter Drive/Bendix: Testing and Inspection Drive Clutch Failure - A/C Delco The overrunning clutch type drive seldom becomes so worn that it fails to engage since it is directly activated by a fork and lever. The only thing that is likely to happen is that, once engaged, it will not turn the engine because the clutch itself is worn out. A much more frequent difficulty and one that rapidly wears ring gear and teeth is partial engagement. Proper meshing of the pinion is controlled by the end clearance between the pinion gear and the starter housing or pinion stop, if used. On some starters, the solenoids are completely enclosed in the starter housing and the pinion clearance is not adjustable. If the clearance is not correct, the starter must be disassembled and checked for excessive wear of solenoid linkage, shift lever mechanism, or improper assembly of parts. Failure of the overrunning clutch drive to disengage is usually caused by binding between the armature shaft and the drive. If the drive, particularly the clutch, shows signs of overheating it indicates that it is not disengaging immediately after the engine starts. If the clutch is forced to overrun too long, it overheats and turns a bluish color. For the cause of the binding, look for rust or gum between the armature shaft and the drive, or for burred splines. Excess oil on the drive will lead to gumming, and inadequate air circulation in the flywheel housing will cause rust. Overrunning clutch drives cannot be overhauled in the field so they must be replaced. In cleaning, never soak them in a solvent because the solvent may enter the clutch and dissolve the sealed-in lubricant. Wipe them off lightly with kerosene and lubricate them sparingly with SAE 10 or 10W oil. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Motor > Starter Drive/Bendix > Component Information > Testing and Inspection > Drive Clutch Failure - A/C Delco > Page 7147 Starter Drive/Bendix: Testing and Inspection Drive Failure - A/C Delco When a Bendix type drive doesn't engage the cause usually is one of three things: either the drive spring is broken, one of the drive spring bolts has sheared off, or the screw shaft threads won't allow the pinion to travel toward the flywheel. In the first two cases, remove the drive by unscrewing the setscrew under the last coil of the drive spring and replace the broken parts. Gummed or rusty screw shaft threads are fairly common causes of Bendix drive failure and are easily cleaned with a little kerosene or steel wool, depending on the trouble. Here again, as in the case of overrunning clutch drives, use light oil sparingly, and be sure the flywheel housing has adequate ventilation. There is usually a breather hole in the bottom of the flywheel housing which should be open. The failure of a Bendix drive to disengage or to mesh properly is most often caused by gummed or rusty screw shaft threads. When this is not true, look for mechanical failure within the drive itself. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Motor > Starter Drive/Bendix > Component Information > Testing and Inspection > Drive Clutch Failure - A/C Delco > Page 7148 Starter Drive/Bendix: Testing and Inspection Starter Drive Troubles - AC Delco Starter drive troubles are easy to diagnose and they usually cannot be confused with ordinary starter difficulties. If the starter does not turn over at all or if it drags, look for trouble in the starter or electrical supply system. Concentrate on the starter drive or ring gear if the starter is noisy, if it turns but does not engage the engine, or if the starter won't disengage after the engine is started. After the starter is removed, the trouble can usually be located quickly. Worn or chipped ring gear or starter pinion are the usual causes of noisy operation. Before replacing either or both of these parts try to find out what caused the damage. With the Bendix type drive, incomplete engagement of the pinion with the ring gear is a common cause of tooth damage. The wrong pinion clearance on starter drives of the overrunning clutch type leads to poor meshing of the pinion and ring gear and too rapid tooth wear. A less common cause of noise with either type of drive is a bent starter armature shaft. When this shaft is bent, the pinion gear alternately binds and then only partly meshes with the ring gear. Most manufacturers specify a maximum of 0.003 inch radial runout on the armature shaft. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Locations Lower Right Side Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions Starter Solenoid: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7154 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7155 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7156 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7157 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7158 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7159 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7160 Starter Solenoid: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7161 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7162 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7163 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7164 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7165 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7166 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7167 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7168 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7169 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7170 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7171 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7172 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7173 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7174 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7175 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7176 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7177 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7178 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7179 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7180 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7181 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7182 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7183 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Diagram Information and Instructions > Page 7184 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Starting System > Starter Solenoid > Component Information > Diagrams > Page 7185 Starter Solenoid: Description and Operation DESCRIPTION The solenoid switch on a cranking motor not only closes the circuit between the battery and the cranking motor but also shifts the drive pinion into mesh with the engine flywheel ring gear. This is done by means of a linkage between the solenoid switch plunger and the shift lever on the cranking motor. OPERATION There are two windings in the solenoid; a pull-in winding and a hold-in winding. Both windings are energized when the external control switch is closed. They produce a magnetic field which pulls the plunger in so that the drive pinion is shifted into mesh, and the main contacts in the solenoid switch are closed to connect the battery directly to the cranking motor. Closing the main switch contacts shorts out the pull-in winding since this winding is connected across the main contacts. The magnetism produced by the hold-in winding is sufficient to hold the plunger in, and shorting out the pull-in winding reduces drain on the battery. When the control switch is opened, it disconnects the hold-in winding from the battery. When the hold-in winding is disconnected from the battery, the shift lever spring withdraws the plunger from the solenoid, opening the solenoid switch contacts and at the same time withdrawing the drive pinion from mesh. Proper operation of the switch depends on maintaining a definite balance between the magnetic strength of the pull-in and hold-in windings. This balance is established in the design by the size of the wire and the number of turns specified. An open circuit in the hold-in winding or attempts to crank with a discharged battery will cause the switch to chatter. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Auxiliary Power Outlet > Component Information > Technical Service Bulletins > Customer Interest for Auxiliary Power Outlet: > 99-08-45-005 > Nov > 99 > Accessory Receptacle/Cigar Lighter - Inoperative Auxiliary Power Outlet: Customer Interest Accessory Receptacle/Cigar Lighter - Inoperative File In Section: 08 - Body and Accessories Bulletin No.: 99-08-45-005 Date: November, 1999 TECHNICAL Subject: Accessory Receptacle/Cigar Lighter is Inoperative (Check Aftermarket Device Plug for Short to Ground) Models: 1995-2000 Passenger Cars and Trucks Condition Some customers may comment that the cigar lighter or the accessory receptacle is inoperative; or that the internal fuse (within the plug on an aftermarket device), blows intermittently. Cause Certain aftermarket devices have a newly designed power plug with an internal mini fuse. The mini fuse may have an external terminal (which may be used to externally check the fuse). If the mini fuse external test terminal is not recessed into the mini fuse body, it may come in contact with the shell of the vehicle receptacle and cause the fuse (of either the vehicle or the aftermarket device), to blow intermittently. Correction Test the aftermarket device plug for short to ground. The following step may be performed at the customer's expense. As this is not a defect in material, design or workmanship of the vehicle, it would be the owner's responsibility. 1. Place a piece of tape over the mini fuse terminal temporarily. 2. Explain to the customer that the fuse for the device must have no exposed terminals, and that finding one would be his responsibility. 3. Refer the customer to the manufacturer of the aftermarket device for a new plug. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Auxiliary Power Outlet > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Auxiliary Power Outlet: > 99-08-45-005 > Nov > 99 > Accessory Receptacle/Cigar Lighter - Inoperative Auxiliary Power Outlet: All Technical Service Bulletins Accessory Receptacle/Cigar Lighter Inoperative File In Section: 08 - Body and Accessories Bulletin No.: 99-08-45-005 Date: November, 1999 TECHNICAL Subject: Accessory Receptacle/Cigar Lighter is Inoperative (Check Aftermarket Device Plug for Short to Ground) Models: 1995-2000 Passenger Cars and Trucks Condition Some customers may comment that the cigar lighter or the accessory receptacle is inoperative; or that the internal fuse (within the plug on an aftermarket device), blows intermittently. Cause Certain aftermarket devices have a newly designed power plug with an internal mini fuse. The mini fuse may have an external terminal (which may be used to externally check the fuse). If the mini fuse external test terminal is not recessed into the mini fuse body, it may come in contact with the shell of the vehicle receptacle and cause the fuse (of either the vehicle or the aftermarket device), to blow intermittently. Correction Test the aftermarket device plug for short to ground. The following step may be performed at the customer's expense. As this is not a defect in material, design or workmanship of the vehicle, it would be the owner's responsibility. 1. Place a piece of tape over the mini fuse terminal temporarily. 2. Explain to the customer that the fuse for the device must have no exposed terminals, and that finding one would be his responsibility. 3. Refer the customer to the manufacturer of the aftermarket device for a new plug. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Circuit Breaker > Component Information > Locations Fuse Block Details: Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Circuit Breaker > Component Information > Locations > Page 7203 Fuse Block Details: Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Underhood Electrical Center <--> [Electrical Accessory Panel] > Component Information > Locations > Fuse Block Detail: Underhood Electrical Center U/Hood Electrical Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Underhood Electrical Center <--> [Electrical Accessory Panel] > Component Information > Locations > Fuse Block Detail: Underhood Electrical Center > Page 7208 Underhood Electrical Center: Locations Underhood Electrical Center Engine Compartment Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Underhood Electrical Center <--> [Electrical Accessory Panel] > Component Information > Locations > Page 7209 U/Hood Electrical Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Technical Service Bulletins > Electrical - Aftermarket Fuse Warning Fuse: Technical Service Bulletins Electrical - Aftermarket Fuse Warning Bulletin No.: 07-08-45-002 Date: September 05, 2007 ADVANCED SERVICE INFORMATION Subject: Service Alert: Concerns With Aftermarket Fuses in GM Vehicles Models: 2008 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2008 and Prior HUMMER H2, H3 2008 and Prior Saab 9-7X Concerns with Harbor Freight Tools "Storehouse" Branded Blade Type Fuses General Motors has become aware of a fuse recall by Harbor Freight Tools/Storehouse for a variety of aftermarket fuses. In two cases, these fuses have not provided protection for the wiring system of the vehicles they were customer installed in. Upon testing the 15 amp version, it was found that the fuse still would not "open" when shorted directly across the battery terminals. How to Identify These Fuses Packed in a 120 piece set, the fuse has a translucent, hard plastic, blue body with the amperage stamped into the top. There are no white painted numbers on the fuse to indicate amperage. There are no identifying marks on the fuse to tell who is making it. The fuses are known to be distributed by Harbor Freight Tools but there may be other marketers, and packaging of this style of fuse. It would be prudent to replace these fuses if found in a customers vehicle. Likewise, if wiring overheating is found you should check the fuse panel for the presence of this style of fuse. All GM dealers should use genuine GM fuses on the vehicles they service. You should also encourage the use of GM fuses to your customers to assure they are getting the required electrical system protection. GM has no knowledge of any concerns with other aftermarket fuses. If additional information becomes available, this bulletin will be updated. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Locations > I/P Fuse Block LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Locations > I/P Fuse Block > Page 7216 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label Fuse: Application and ID Instrument Panel (I/P) Fuse Block Label I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7219 I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7220 Fuse: Application and ID Under Hood Electrical Center Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7221 Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse > Component Information > Application and ID > Page 7222 I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) Fuse Block: Locations Auxiliary Fuse Block, Special Equipment Option (Seo) Under I/P Behind LH I/P, Left Of Brake Pedal Bracket Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 7227 Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 7228 LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 7229 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label Fuse Block: Application and ID Instrument Panel (I/P) Fuse Block Label I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7232 I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7233 Fuse Block: Application and ID Under Hood Electrical Center Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair Grounding Point: Technical Service Bulletins Electrical - Information For Electrical Ground Repair INFORMATION Bulletin No.: 10-08-45-001B Date: October 25, 2010 Subject: Information for Electrical Ground Repair - Use New Replacement Fasteners with Conductive Finish Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2011 model year and update the Warranty Information. Please discard Corporate Bulletin Number 10-08-45-001A (Section 08 - Body and Accessories). Electrical Ground Repair Overview Proper electrical system function relies on secure, stable and corrosion-free electrical ground connections. Loose, stripped, or corroded connections increase the possibility of improper system function and loss of module communication. These conditions may also lead to unnecessary repairs and component replacement. In general, electrical ground connections are accomplished using one, or a combination of the following attachment methods: - Welded M6 stud and nut - Welded M6 nut and bolt - Welded M8 nut and bolt Determine which attachment method is used and perform the appropriate or alternative repair as described in this bulletin. M6 Weld Stud Replacement Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. Select a location adjacent the damaged or missing M6 ground stud having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 3. Drill a 10 mm (0.40 in) diameter hole through the panel. 4. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7238 Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 5. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 6. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 7. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 8. Ensure the rivet stud is securely fastened, WITHOUT ANY detectable movement. 9. Completely wrap the threads of the rivet stud with painters tape or equivalent. Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 10. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 11. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 12. Remove the painters tape or equivalent from the rivet stud threads. 13. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 14. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7239 15. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 16. Install the electrical ground wire terminal to the rivet stud. 17. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 18. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in). 19. Verify proper system operation. M6 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M6 weld nut at the electrical ground location is damaged or stripped, a M7 conductive self-threading bolt may be used to secure the ground wire terminal. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the weld nut and allow to dry. 3. Remove any loose metal particles from the damaged or stripped weld nut with a stiff brush. 4. Select a M7 conductive self-threading bolt. Refer to the Parts Information section of this bulletin 5. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M7 conductive self-threading bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 6. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 7. Install the electrical ground wire terminal to the M7 conductive self-threading bolt. 8. Install the M7 conductive self-threading bolt and: Tighten Tighten to 9 Nm (80 lb in). 9. Verify proper system operation. M6 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the electrical ground location is accessible from both sides of the panel, a M6 conductive bolt and a M6 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the damaged M6 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 8.5 mm (0.33 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 8.5 mm (0.33 in) hole until bare metal is visible. 6. Select a M6 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M6 conductive bolt to the ground location. 10. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M6 conductive nut to the bolt and: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7240 Tighten Tighten to 8 Nm (71 lb in). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is accessible from both sides of the panel, a M8 conductive bolt and a M8 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. 6. Select a M8 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M8 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M8 conductive bolt to the ground location. 10. Select a M8 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M8 conductive nut to the bolt and: Tighten Tighten to 22 Nm (16 lb ft). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is not accessible from both sides of the panel, a M6 conductive rivet stud and a M6 conductive nut may be used to secure the electrical ground wire terminal. 2. Select a location adjacent the damaged M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7241 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) until bare metal is visible. Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 6. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 7. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 8. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 9. Ensure the new rivet stud is securely fastened, WITHOUT ANY detectable movement. 10. Completely wrap the threads of the rivet stud with painters tape or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7242 Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the electrical ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 11. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 12. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 13. Remove the painters tape or equivalent from the rivet stud threads. 14. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 15. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 16. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 17. Install the electrical ground wire terminal to the M6 conductive rivet stud. 18. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 19. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in) 20. Verify proper system operation. Parts Information Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7243 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Auxiliary Juction Block <--> [Multiple Junction Connector] > Component Information > Locations Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center Convenience Center: Locations Convenience Center LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7252 Behind LH I/P, Left Of Brake Pedal Bracket LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7253 Under I/P Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7254 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Page 7255 Convenience Center: Application and ID Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center Convenience Center: Locations Convenience Center LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7260 Behind LH I/P, Left Of Brake Pedal Bracket LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7261 Under I/P Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7262 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Page 7263 Convenience Center: Application and ID Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Wiring Harness: Customer Interest Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7272 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7273 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7274 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Wiring Harness: All Technical Service Bulletins Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7280 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7281 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7282 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair Wiring Harness: All Technical Service Bulletins Electrical - Information For Electrical Ground Repair INFORMATION Bulletin No.: 10-08-45-001B Date: October 25, 2010 Subject: Information for Electrical Ground Repair - Use New Replacement Fasteners with Conductive Finish Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2011 model year and update the Warranty Information. Please discard Corporate Bulletin Number 10-08-45-001A (Section 08 - Body and Accessories). Electrical Ground Repair Overview Proper electrical system function relies on secure, stable and corrosion-free electrical ground connections. Loose, stripped, or corroded connections increase the possibility of improper system function and loss of module communication. These conditions may also lead to unnecessary repairs and component replacement. In general, electrical ground connections are accomplished using one, or a combination of the following attachment methods: - Welded M6 stud and nut - Welded M6 nut and bolt - Welded M8 nut and bolt Determine which attachment method is used and perform the appropriate or alternative repair as described in this bulletin. M6 Weld Stud Replacement Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. Select a location adjacent the damaged or missing M6 ground stud having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 3. Drill a 10 mm (0.40 in) diameter hole through the panel. 4. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7287 Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 5. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 6. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 7. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 8. Ensure the rivet stud is securely fastened, WITHOUT ANY detectable movement. 9. Completely wrap the threads of the rivet stud with painters tape or equivalent. Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 10. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 11. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 12. Remove the painters tape or equivalent from the rivet stud threads. 13. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 14. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7288 15. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 16. Install the electrical ground wire terminal to the rivet stud. 17. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 18. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in). 19. Verify proper system operation. M6 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M6 weld nut at the electrical ground location is damaged or stripped, a M7 conductive self-threading bolt may be used to secure the ground wire terminal. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the weld nut and allow to dry. 3. Remove any loose metal particles from the damaged or stripped weld nut with a stiff brush. 4. Select a M7 conductive self-threading bolt. Refer to the Parts Information section of this bulletin 5. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M7 conductive self-threading bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 6. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 7. Install the electrical ground wire terminal to the M7 conductive self-threading bolt. 8. Install the M7 conductive self-threading bolt and: Tighten Tighten to 9 Nm (80 lb in). 9. Verify proper system operation. M6 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the electrical ground location is accessible from both sides of the panel, a M6 conductive bolt and a M6 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the damaged M6 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 8.5 mm (0.33 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 8.5 mm (0.33 in) hole until bare metal is visible. 6. Select a M6 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M6 conductive bolt to the ground location. 10. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M6 conductive nut to the bolt and: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7289 Tighten Tighten to 8 Nm (71 lb in). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is accessible from both sides of the panel, a M8 conductive bolt and a M8 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. 6. Select a M8 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M8 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M8 conductive bolt to the ground location. 10. Select a M8 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M8 conductive nut to the bolt and: Tighten Tighten to 22 Nm (16 lb ft). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is not accessible from both sides of the panel, a M6 conductive rivet stud and a M6 conductive nut may be used to secure the electrical ground wire terminal. 2. Select a location adjacent the damaged M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7290 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) until bare metal is visible. Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 6. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 7. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 8. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 9. Ensure the new rivet stud is securely fastened, WITHOUT ANY detectable movement. 10. Completely wrap the threads of the rivet stud with painters tape or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7291 Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the electrical ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 11. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 12. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 13. Remove the painters tape or equivalent from the rivet stud threads. 14. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 15. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 16. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 17. Install the electrical ground wire terminal to the M6 conductive rivet stud. 18. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 19. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in) 20. Verify proper system operation. Parts Information Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7292 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair Wiring Harness: All Technical Service Bulletins Electrical - Instrument Panel & General Wiring Repair Bulletin No.: 06-08-45-004 Date: May 02, 2006 INFORMATION Subject: Instrument Panel (I/P), Body and General Wiring Harness Repair Models: 2007 and Prior GM Cars and Trucks 2003-2007 HUMMER H2 2006-2007 HUMMER H3 Important: A part restriction has been implemented on all Body and I/P harnesses and is being administered by the PQC. If a body or I/P harness replacement is required, it can take 12-28 weeks for a harness to be built and delivered to a dealer. The dealer technician is expected to repair any harness damage as the first and best choice before replacing a harness. In an effort to standardize repair practices, General Motors is requiring that all wiring harnesses be repaired instead of replaced. If there is a question concerning which connector and/or terminal you are working on, refer to the information in the appropriate Connector End Views in SI. The Instruction Manual J 38125-620, which is sent with each new update of the J 38125 Terminal Repair Kit, also has terminal crimping and terminal remove information. Important: There are some parts in the J 38125 Terminal Repair Kit (i.e. SIR connector CPAs and heat shrink tube (used in high heat area pigtail replacement) and some TPAs that are not available from GMSPO. It is vitally important that each update to the J 38125 Terminal Repair Kit be done as soon as it arrives at the dealer. Utilize the Terminal Repair Kit (J 38125) to achieve an effective wiring repair. The Terminal Repair Kit has been an essential tool for all GM Dealers since 1987. Replacement terminals and tools for this kit are available through SPX/Kent Moore. Refer to Corporate Bulletin Number 06-08-45-001 for more information. The Instruction Manual J 38125-620, which is sent with each new update to the J 38125 Terminal Repair Kit, also has terminal crimping and terminal removal information. U.S. Dealers Only - Training courses (including Tech Assists, Emerging Issues, Web, IDL and Hands-on) are available through the GM Training website. Refer to Resources and then Training Materials for a complete list of available courses. Canadian Dealers Only - Refer to the Training section of GM infoNet for a complete list of available courses and a copy of the J 38125 Terminal Repair Kit Instruction Manual. Wiring repair information is also available in Service Information (SI). The Wiring Repair section contains information for the following types of wiring repairs: - Testing for intermittent conditions and poor conditions - Flat wire repairs - GMLAN wiring repairs - High temperature wiring repairs - Splicing copper wire using splice clips - Splicing copper wire using splice sleeves - Splicing twisted or shielded cable - Splicing inline harness diodes Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair > Page 7297 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair Wiring Harness: All Technical Service Bulletins Electrical - Information For Electrical Ground Repair INFORMATION Bulletin No.: 10-08-45-001B Date: October 25, 2010 Subject: Information for Electrical Ground Repair - Use New Replacement Fasteners with Conductive Finish Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2011 model year and update the Warranty Information. Please discard Corporate Bulletin Number 10-08-45-001A (Section 08 - Body and Accessories). Electrical Ground Repair Overview Proper electrical system function relies on secure, stable and corrosion-free electrical ground connections. Loose, stripped, or corroded connections increase the possibility of improper system function and loss of module communication. These conditions may also lead to unnecessary repairs and component replacement. In general, electrical ground connections are accomplished using one, or a combination of the following attachment methods: - Welded M6 stud and nut - Welded M6 nut and bolt - Welded M8 nut and bolt Determine which attachment method is used and perform the appropriate or alternative repair as described in this bulletin. M6 Weld Stud Replacement Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. Select a location adjacent the damaged or missing M6 ground stud having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 3. Drill a 10 mm (0.40 in) diameter hole through the panel. 4. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7303 Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 5. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 6. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 7. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 8. Ensure the rivet stud is securely fastened, WITHOUT ANY detectable movement. 9. Completely wrap the threads of the rivet stud with painters tape or equivalent. Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 10. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 11. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 12. Remove the painters tape or equivalent from the rivet stud threads. 13. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 14. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7304 15. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 16. Install the electrical ground wire terminal to the rivet stud. 17. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 18. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in). 19. Verify proper system operation. M6 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M6 weld nut at the electrical ground location is damaged or stripped, a M7 conductive self-threading bolt may be used to secure the ground wire terminal. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the weld nut and allow to dry. 3. Remove any loose metal particles from the damaged or stripped weld nut with a stiff brush. 4. Select a M7 conductive self-threading bolt. Refer to the Parts Information section of this bulletin 5. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M7 conductive self-threading bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 6. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 7. Install the electrical ground wire terminal to the M7 conductive self-threading bolt. 8. Install the M7 conductive self-threading bolt and: Tighten Tighten to 9 Nm (80 lb in). 9. Verify proper system operation. M6 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the electrical ground location is accessible from both sides of the panel, a M6 conductive bolt and a M6 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the damaged M6 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 8.5 mm (0.33 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 8.5 mm (0.33 in) hole until bare metal is visible. 6. Select a M6 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M6 conductive bolt to the ground location. 10. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M6 conductive nut to the bolt and: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7305 Tighten Tighten to 8 Nm (71 lb in). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is accessible from both sides of the panel, a M8 conductive bolt and a M8 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. 6. Select a M8 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M8 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M8 conductive bolt to the ground location. 10. Select a M8 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M8 conductive nut to the bolt and: Tighten Tighten to 22 Nm (16 lb ft). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is not accessible from both sides of the panel, a M6 conductive rivet stud and a M6 conductive nut may be used to secure the electrical ground wire terminal. 2. Select a location adjacent the damaged M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7306 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) until bare metal is visible. Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 6. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 7. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 8. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 9. Ensure the new rivet stud is securely fastened, WITHOUT ANY detectable movement. 10. Completely wrap the threads of the rivet stud with painters tape or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7307 Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the electrical ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 11. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 12. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 13. Remove the painters tape or equivalent from the rivet stud threads. 14. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 15. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 16. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 17. Install the electrical ground wire terminal to the M6 conductive rivet stud. 18. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 19. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in) 20. Verify proper system operation. Parts Information Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7308 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair Wiring Harness: All Technical Service Bulletins Electrical - Instrument Panel & General Wiring Repair Bulletin No.: 06-08-45-004 Date: May 02, 2006 INFORMATION Subject: Instrument Panel (I/P), Body and General Wiring Harness Repair Models: 2007 and Prior GM Cars and Trucks 2003-2007 HUMMER H2 2006-2007 HUMMER H3 Important: A part restriction has been implemented on all Body and I/P harnesses and is being administered by the PQC. If a body or I/P harness replacement is required, it can take 12-28 weeks for a harness to be built and delivered to a dealer. The dealer technician is expected to repair any harness damage as the first and best choice before replacing a harness. In an effort to standardize repair practices, General Motors is requiring that all wiring harnesses be repaired instead of replaced. If there is a question concerning which connector and/or terminal you are working on, refer to the information in the appropriate Connector End Views in SI. The Instruction Manual J 38125-620, which is sent with each new update of the J 38125 Terminal Repair Kit, also has terminal crimping and terminal remove information. Important: There are some parts in the J 38125 Terminal Repair Kit (i.e. SIR connector CPAs and heat shrink tube (used in high heat area pigtail replacement) and some TPAs that are not available from GMSPO. It is vitally important that each update to the J 38125 Terminal Repair Kit be done as soon as it arrives at the dealer. Utilize the Terminal Repair Kit (J 38125) to achieve an effective wiring repair. The Terminal Repair Kit has been an essential tool for all GM Dealers since 1987. Replacement terminals and tools for this kit are available through SPX/Kent Moore. Refer to Corporate Bulletin Number 06-08-45-001 for more information. The Instruction Manual J 38125-620, which is sent with each new update to the J 38125 Terminal Repair Kit, also has terminal crimping and terminal removal information. U.S. Dealers Only - Training courses (including Tech Assists, Emerging Issues, Web, IDL and Hands-on) are available through the GM Training website. Refer to Resources and then Training Materials for a complete list of available courses. Canadian Dealers Only - Refer to the Training section of GM infoNet for a complete list of available courses and a copy of the J 38125 Terminal Repair Kit Instruction Manual. Wiring repair information is also available in Service Information (SI). The Wiring Repair section contains information for the following types of wiring repairs: - Testing for intermittent conditions and poor conditions - Flat wire repairs - GMLAN wiring repairs - High temperature wiring repairs - Splicing copper wire using splice clips - Splicing copper wire using splice sleeves - Splicing twisted or shielded cable - Splicing inline harness diodes Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Starting and Charging > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair > Page 7313 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Auxiliary Power Outlet > Component Information > Technical Service Bulletins > Customer Interest for Auxiliary Power Outlet: > 99-08-45-005 > Nov > 99 > Accessory Receptacle/Cigar Lighter - Inoperative Auxiliary Power Outlet: Customer Interest Accessory Receptacle/Cigar Lighter - Inoperative File In Section: 08 - Body and Accessories Bulletin No.: 99-08-45-005 Date: November, 1999 TECHNICAL Subject: Accessory Receptacle/Cigar Lighter is Inoperative (Check Aftermarket Device Plug for Short to Ground) Models: 1995-2000 Passenger Cars and Trucks Condition Some customers may comment that the cigar lighter or the accessory receptacle is inoperative; or that the internal fuse (within the plug on an aftermarket device), blows intermittently. Cause Certain aftermarket devices have a newly designed power plug with an internal mini fuse. The mini fuse may have an external terminal (which may be used to externally check the fuse). If the mini fuse external test terminal is not recessed into the mini fuse body, it may come in contact with the shell of the vehicle receptacle and cause the fuse (of either the vehicle or the aftermarket device), to blow intermittently. Correction Test the aftermarket device plug for short to ground. The following step may be performed at the customer's expense. As this is not a defect in material, design or workmanship of the vehicle, it would be the owner's responsibility. 1. Place a piece of tape over the mini fuse terminal temporarily. 2. Explain to the customer that the fuse for the device must have no exposed terminals, and that finding one would be his responsibility. 3. Refer the customer to the manufacturer of the aftermarket device for a new plug. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Auxiliary Power Outlet > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Auxiliary Power Outlet: > 99-08-45-005 > Nov > 99 > Accessory Receptacle/Cigar Lighter - Inoperative Auxiliary Power Outlet: All Technical Service Bulletins Accessory Receptacle/Cigar Lighter Inoperative File In Section: 08 - Body and Accessories Bulletin No.: 99-08-45-005 Date: November, 1999 TECHNICAL Subject: Accessory Receptacle/Cigar Lighter is Inoperative (Check Aftermarket Device Plug for Short to Ground) Models: 1995-2000 Passenger Cars and Trucks Condition Some customers may comment that the cigar lighter or the accessory receptacle is inoperative; or that the internal fuse (within the plug on an aftermarket device), blows intermittently. Cause Certain aftermarket devices have a newly designed power plug with an internal mini fuse. The mini fuse may have an external terminal (which may be used to externally check the fuse). If the mini fuse external test terminal is not recessed into the mini fuse body, it may come in contact with the shell of the vehicle receptacle and cause the fuse (of either the vehicle or the aftermarket device), to blow intermittently. Correction Test the aftermarket device plug for short to ground. The following step may be performed at the customer's expense. As this is not a defect in material, design or workmanship of the vehicle, it would be the owner's responsibility. 1. Place a piece of tape over the mini fuse terminal temporarily. 2. Explain to the customer that the fuse for the device must have no exposed terminals, and that finding one would be his responsibility. 3. Refer the customer to the manufacturer of the aftermarket device for a new plug. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Circuit Breaker > Component Information > Locations Fuse Block Details: Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Circuit Breaker > Component Information > Locations > Page 7331 Fuse Block Details: Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Underhood Electrical Center <--> [Electrical Accessory Panel] > Component Information > Locations > Fuse Block Detail: Underhood Electrical Center U/Hood Electrical Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Underhood Electrical Center <--> [Electrical Accessory Panel] > Component Information > Locations > Fuse Block Detail: Underhood Electrical Center > Page 7336 Underhood Electrical Center: Locations Underhood Electrical Center Engine Compartment Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Underhood Electrical Center <--> [Electrical Accessory Panel] > Component Information > Locations > Page 7337 U/Hood Electrical Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Technical Service Bulletins > Electrical - Aftermarket Fuse Warning Fuse: Technical Service Bulletins Electrical - Aftermarket Fuse Warning Bulletin No.: 07-08-45-002 Date: September 05, 2007 ADVANCED SERVICE INFORMATION Subject: Service Alert: Concerns With Aftermarket Fuses in GM Vehicles Models: 2008 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2008 and Prior HUMMER H2, H3 2008 and Prior Saab 9-7X Concerns with Harbor Freight Tools "Storehouse" Branded Blade Type Fuses General Motors has become aware of a fuse recall by Harbor Freight Tools/Storehouse for a variety of aftermarket fuses. In two cases, these fuses have not provided protection for the wiring system of the vehicles they were customer installed in. Upon testing the 15 amp version, it was found that the fuse still would not "open" when shorted directly across the battery terminals. How to Identify These Fuses Packed in a 120 piece set, the fuse has a translucent, hard plastic, blue body with the amperage stamped into the top. There are no white painted numbers on the fuse to indicate amperage. There are no identifying marks on the fuse to tell who is making it. The fuses are known to be distributed by Harbor Freight Tools but there may be other marketers, and packaging of this style of fuse. It would be prudent to replace these fuses if found in a customers vehicle. Likewise, if wiring overheating is found you should check the fuse panel for the presence of this style of fuse. All GM dealers should use genuine GM fuses on the vehicles they service. You should also encourage the use of GM fuses to your customers to assure they are getting the required electrical system protection. GM has no knowledge of any concerns with other aftermarket fuses. If additional information becomes available, this bulletin will be updated. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Locations > I/P Fuse Block LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Locations > I/P Fuse Block > Page 7344 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label Fuse: Application and ID Instrument Panel (I/P) Fuse Block Label I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7347 I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7348 Fuse: Application and ID Under Hood Electrical Center Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Usage Chart Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7349 Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse > Component Information > Application and ID > Page 7350 I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) Fuse Block: Locations Auxiliary Fuse Block, Special Equipment Option (Seo) Under I/P Behind LH I/P, Left Of Brake Pedal Bracket Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 7355 Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 7356 LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse Block > Component Information > Locations > Auxiliary Fuse Block, Special Equipment Option (Seo) > Page 7357 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label Fuse Block: Application and ID Instrument Panel (I/P) Fuse Block Label I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7360 I/P Fuse Block I/P Fuse Block Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Fuse Block > Component Information > Application and ID > Instrument Panel (I/P) Fuse Block Label > Page 7361 Fuse Block: Application and ID Under Hood Electrical Center Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair Grounding Point: Technical Service Bulletins Electrical - Information For Electrical Ground Repair INFORMATION Bulletin No.: 10-08-45-001B Date: October 25, 2010 Subject: Information for Electrical Ground Repair - Use New Replacement Fasteners with Conductive Finish Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2011 model year and update the Warranty Information. Please discard Corporate Bulletin Number 10-08-45-001A (Section 08 - Body and Accessories). Electrical Ground Repair Overview Proper electrical system function relies on secure, stable and corrosion-free electrical ground connections. Loose, stripped, or corroded connections increase the possibility of improper system function and loss of module communication. These conditions may also lead to unnecessary repairs and component replacement. In general, electrical ground connections are accomplished using one, or a combination of the following attachment methods: - Welded M6 stud and nut - Welded M6 nut and bolt - Welded M8 nut and bolt Determine which attachment method is used and perform the appropriate or alternative repair as described in this bulletin. M6 Weld Stud Replacement Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. Select a location adjacent the damaged or missing M6 ground stud having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 3. Drill a 10 mm (0.40 in) diameter hole through the panel. 4. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7366 Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 5. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 6. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 7. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 8. Ensure the rivet stud is securely fastened, WITHOUT ANY detectable movement. 9. Completely wrap the threads of the rivet stud with painters tape or equivalent. Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 10. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 11. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 12. Remove the painters tape or equivalent from the rivet stud threads. 13. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 14. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7367 15. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 16. Install the electrical ground wire terminal to the rivet stud. 17. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 18. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in). 19. Verify proper system operation. M6 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M6 weld nut at the electrical ground location is damaged or stripped, a M7 conductive self-threading bolt may be used to secure the ground wire terminal. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the weld nut and allow to dry. 3. Remove any loose metal particles from the damaged or stripped weld nut with a stiff brush. 4. Select a M7 conductive self-threading bolt. Refer to the Parts Information section of this bulletin 5. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M7 conductive self-threading bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 6. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 7. Install the electrical ground wire terminal to the M7 conductive self-threading bolt. 8. Install the M7 conductive self-threading bolt and: Tighten Tighten to 9 Nm (80 lb in). 9. Verify proper system operation. M6 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the electrical ground location is accessible from both sides of the panel, a M6 conductive bolt and a M6 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the damaged M6 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 8.5 mm (0.33 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 8.5 mm (0.33 in) hole until bare metal is visible. 6. Select a M6 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M6 conductive bolt to the ground location. 10. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M6 conductive nut to the bolt and: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7368 Tighten Tighten to 8 Nm (71 lb in). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is accessible from both sides of the panel, a M8 conductive bolt and a M8 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. 6. Select a M8 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M8 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M8 conductive bolt to the ground location. 10. Select a M8 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M8 conductive nut to the bolt and: Tighten Tighten to 22 Nm (16 lb ft). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is not accessible from both sides of the panel, a M6 conductive rivet stud and a M6 conductive nut may be used to secure the electrical ground wire terminal. 2. Select a location adjacent the damaged M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7369 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) until bare metal is visible. Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 6. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 7. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 8. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 9. Ensure the new rivet stud is securely fastened, WITHOUT ANY detectable movement. 10. Completely wrap the threads of the rivet stud with painters tape or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7370 Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the electrical ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 11. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 12. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 13. Remove the painters tape or equivalent from the rivet stud threads. 14. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 15. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 16. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 17. Install the electrical ground wire terminal to the M6 conductive rivet stud. 18. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 19. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in) 20. Verify proper system operation. Parts Information Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Grounding Point > Component Information > Technical Service Bulletins > Electrical - Information For Electrical Ground Repair > Page 7371 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Auxiliary Juction Block <--> [Multiple Junction Connector] > Component Information > Locations Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center Convenience Center: Locations Convenience Center LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7380 Behind LH I/P, Left Of Brake Pedal Bracket LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7381 Under I/P Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7382 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Relays and Modules - Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Page 7383 Convenience Center: Application and ID Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center Convenience Center: Locations Convenience Center LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7388 Behind LH I/P, Left Of Brake Pedal Bracket LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7389 Under I/P Under I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Convenience Center > Page 7390 Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Convenience Center <--> [Relay Box] > Component Information > Locations > Page 7391 Convenience Center: Application and ID Fuse Block Details: Fuse Usage Chart Underhood Electrical Center Fuse Block Details Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Wiring Harness: Customer Interest Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7400 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7401 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > Customer Interest: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7402 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Wiring Harness: All Technical Service Bulletins Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7408 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7409 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 7410 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair Wiring Harness: All Technical Service Bulletins Electrical - Information For Electrical Ground Repair INFORMATION Bulletin No.: 10-08-45-001B Date: October 25, 2010 Subject: Information for Electrical Ground Repair - Use New Replacement Fasteners with Conductive Finish Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2011 model year and update the Warranty Information. Please discard Corporate Bulletin Number 10-08-45-001A (Section 08 - Body and Accessories). Electrical Ground Repair Overview Proper electrical system function relies on secure, stable and corrosion-free electrical ground connections. Loose, stripped, or corroded connections increase the possibility of improper system function and loss of module communication. These conditions may also lead to unnecessary repairs and component replacement. In general, electrical ground connections are accomplished using one, or a combination of the following attachment methods: - Welded M6 stud and nut - Welded M6 nut and bolt - Welded M8 nut and bolt Determine which attachment method is used and perform the appropriate or alternative repair as described in this bulletin. M6 Weld Stud Replacement Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. Select a location adjacent the damaged or missing M6 ground stud having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 3. Drill a 10 mm (0.40 in) diameter hole through the panel. 4. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7415 Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 5. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 6. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 7. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 8. Ensure the rivet stud is securely fastened, WITHOUT ANY detectable movement. 9. Completely wrap the threads of the rivet stud with painters tape or equivalent. Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 10. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 11. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 12. Remove the painters tape or equivalent from the rivet stud threads. 13. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 14. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7416 15. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 16. Install the electrical ground wire terminal to the rivet stud. 17. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 18. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in). 19. Verify proper system operation. M6 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M6 weld nut at the electrical ground location is damaged or stripped, a M7 conductive self-threading bolt may be used to secure the ground wire terminal. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the weld nut and allow to dry. 3. Remove any loose metal particles from the damaged or stripped weld nut with a stiff brush. 4. Select a M7 conductive self-threading bolt. Refer to the Parts Information section of this bulletin 5. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M7 conductive self-threading bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 6. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 7. Install the electrical ground wire terminal to the M7 conductive self-threading bolt. 8. Install the M7 conductive self-threading bolt and: Tighten Tighten to 9 Nm (80 lb in). 9. Verify proper system operation. M6 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the electrical ground location is accessible from both sides of the panel, a M6 conductive bolt and a M6 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the damaged M6 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 8.5 mm (0.33 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 8.5 mm (0.33 in) hole until bare metal is visible. 6. Select a M6 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M6 conductive bolt to the ground location. 10. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M6 conductive nut to the bolt and: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7417 Tighten Tighten to 8 Nm (71 lb in). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is accessible from both sides of the panel, a M8 conductive bolt and a M8 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. 6. Select a M8 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M8 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M8 conductive bolt to the ground location. 10. Select a M8 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M8 conductive nut to the bolt and: Tighten Tighten to 22 Nm (16 lb ft). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is not accessible from both sides of the panel, a M6 conductive rivet stud and a M6 conductive nut may be used to secure the electrical ground wire terminal. 2. Select a location adjacent the damaged M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7418 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) until bare metal is visible. Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 6. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 7. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 8. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 9. Ensure the new rivet stud is securely fastened, WITHOUT ANY detectable movement. 10. Completely wrap the threads of the rivet stud with painters tape or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7419 Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the electrical ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 11. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 12. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 13. Remove the painters tape or equivalent from the rivet stud threads. 14. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 15. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 16. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 17. Install the electrical ground wire terminal to the M6 conductive rivet stud. 18. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 19. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in) 20. Verify proper system operation. Parts Information Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7420 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair Wiring Harness: All Technical Service Bulletins Electrical - Instrument Panel & General Wiring Repair Bulletin No.: 06-08-45-004 Date: May 02, 2006 INFORMATION Subject: Instrument Panel (I/P), Body and General Wiring Harness Repair Models: 2007 and Prior GM Cars and Trucks 2003-2007 HUMMER H2 2006-2007 HUMMER H3 Important: A part restriction has been implemented on all Body and I/P harnesses and is being administered by the PQC. If a body or I/P harness replacement is required, it can take 12-28 weeks for a harness to be built and delivered to a dealer. The dealer technician is expected to repair any harness damage as the first and best choice before replacing a harness. In an effort to standardize repair practices, General Motors is requiring that all wiring harnesses be repaired instead of replaced. If there is a question concerning which connector and/or terminal you are working on, refer to the information in the appropriate Connector End Views in SI. The Instruction Manual J 38125-620, which is sent with each new update of the J 38125 Terminal Repair Kit, also has terminal crimping and terminal remove information. Important: There are some parts in the J 38125 Terminal Repair Kit (i.e. SIR connector CPAs and heat shrink tube (used in high heat area pigtail replacement) and some TPAs that are not available from GMSPO. It is vitally important that each update to the J 38125 Terminal Repair Kit be done as soon as it arrives at the dealer. Utilize the Terminal Repair Kit (J 38125) to achieve an effective wiring repair. The Terminal Repair Kit has been an essential tool for all GM Dealers since 1987. Replacement terminals and tools for this kit are available through SPX/Kent Moore. Refer to Corporate Bulletin Number 06-08-45-001 for more information. The Instruction Manual J 38125-620, which is sent with each new update to the J 38125 Terminal Repair Kit, also has terminal crimping and terminal removal information. U.S. Dealers Only - Training courses (including Tech Assists, Emerging Issues, Web, IDL and Hands-on) are available through the GM Training website. Refer to Resources and then Training Materials for a complete list of available courses. Canadian Dealers Only - Refer to the Training section of GM infoNet for a complete list of available courses and a copy of the J 38125 Terminal Repair Kit Instruction Manual. Wiring repair information is also available in Service Information (SI). The Wiring Repair section contains information for the following types of wiring repairs: - Testing for intermittent conditions and poor conditions - Flat wire repairs - GMLAN wiring repairs - High temperature wiring repairs - Splicing copper wire using splice clips - Splicing copper wire using splice sleeves - Splicing twisted or shielded cable - Splicing inline harness diodes Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair > Page 7425 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair Wiring Harness: All Technical Service Bulletins Electrical - Information For Electrical Ground Repair INFORMATION Bulletin No.: 10-08-45-001B Date: October 25, 2010 Subject: Information for Electrical Ground Repair - Use New Replacement Fasteners with Conductive Finish Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2011 model year and update the Warranty Information. Please discard Corporate Bulletin Number 10-08-45-001A (Section 08 - Body and Accessories). Electrical Ground Repair Overview Proper electrical system function relies on secure, stable and corrosion-free electrical ground connections. Loose, stripped, or corroded connections increase the possibility of improper system function and loss of module communication. These conditions may also lead to unnecessary repairs and component replacement. In general, electrical ground connections are accomplished using one, or a combination of the following attachment methods: - Welded M6 stud and nut - Welded M6 nut and bolt - Welded M8 nut and bolt Determine which attachment method is used and perform the appropriate or alternative repair as described in this bulletin. M6 Weld Stud Replacement Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. Select a location adjacent the damaged or missing M6 ground stud having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 3. Drill a 10 mm (0.40 in) diameter hole through the panel. 4. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7431 Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 5. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 6. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 7. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 8. Ensure the rivet stud is securely fastened, WITHOUT ANY detectable movement. 9. Completely wrap the threads of the rivet stud with painters tape or equivalent. Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 10. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 11. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 12. Remove the painters tape or equivalent from the rivet stud threads. 13. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 14. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7432 15. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 16. Install the electrical ground wire terminal to the rivet stud. 17. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 18. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in). 19. Verify proper system operation. M6 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M6 weld nut at the electrical ground location is damaged or stripped, a M7 conductive self-threading bolt may be used to secure the ground wire terminal. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the weld nut and allow to dry. 3. Remove any loose metal particles from the damaged or stripped weld nut with a stiff brush. 4. Select a M7 conductive self-threading bolt. Refer to the Parts Information section of this bulletin 5. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M7 conductive self-threading bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 6. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 7. Install the electrical ground wire terminal to the M7 conductive self-threading bolt. 8. Install the M7 conductive self-threading bolt and: Tighten Tighten to 9 Nm (80 lb in). 9. Verify proper system operation. M6 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the electrical ground location is accessible from both sides of the panel, a M6 conductive bolt and a M6 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the damaged M6 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 8.5 mm (0.33 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 8.5 mm (0.33 in) hole until bare metal is visible. 6. Select a M6 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M6 conductive bolt to the ground location. 10. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M6 conductive nut to the bolt and: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7433 Tighten Tighten to 8 Nm (71 lb in). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is accessible from both sides of the panel, a M8 conductive bolt and a M8 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. 6. Select a M8 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M8 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M8 conductive bolt to the ground location. 10. Select a M8 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M8 conductive nut to the bolt and: Tighten Tighten to 22 Nm (16 lb ft). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is not accessible from both sides of the panel, a M6 conductive rivet stud and a M6 conductive nut may be used to secure the electrical ground wire terminal. 2. Select a location adjacent the damaged M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7434 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) until bare metal is visible. Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 6. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 7. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 8. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 9. Ensure the new rivet stud is securely fastened, WITHOUT ANY detectable movement. 10. Completely wrap the threads of the rivet stud with painters tape or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7435 Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the electrical ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 11. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 12. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 13. Remove the painters tape or equivalent from the rivet stud threads. 14. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 15. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 16. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 17. Install the electrical ground wire terminal to the M6 conductive rivet stud. 18. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 19. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in) 20. Verify proper system operation. Parts Information Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 7436 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair Wiring Harness: All Technical Service Bulletins Electrical - Instrument Panel & General Wiring Repair Bulletin No.: 06-08-45-004 Date: May 02, 2006 INFORMATION Subject: Instrument Panel (I/P), Body and General Wiring Harness Repair Models: 2007 and Prior GM Cars and Trucks 2003-2007 HUMMER H2 2006-2007 HUMMER H3 Important: A part restriction has been implemented on all Body and I/P harnesses and is being administered by the PQC. If a body or I/P harness replacement is required, it can take 12-28 weeks for a harness to be built and delivered to a dealer. The dealer technician is expected to repair any harness damage as the first and best choice before replacing a harness. In an effort to standardize repair practices, General Motors is requiring that all wiring harnesses be repaired instead of replaced. If there is a question concerning which connector and/or terminal you are working on, refer to the information in the appropriate Connector End Views in SI. The Instruction Manual J 38125-620, which is sent with each new update of the J 38125 Terminal Repair Kit, also has terminal crimping and terminal remove information. Important: There are some parts in the J 38125 Terminal Repair Kit (i.e. SIR connector CPAs and heat shrink tube (used in high heat area pigtail replacement) and some TPAs that are not available from GMSPO. It is vitally important that each update to the J 38125 Terminal Repair Kit be done as soon as it arrives at the dealer. Utilize the Terminal Repair Kit (J 38125) to achieve an effective wiring repair. The Terminal Repair Kit has been an essential tool for all GM Dealers since 1987. Replacement terminals and tools for this kit are available through SPX/Kent Moore. Refer to Corporate Bulletin Number 06-08-45-001 for more information. The Instruction Manual J 38125-620, which is sent with each new update to the J 38125 Terminal Repair Kit, also has terminal crimping and terminal removal information. U.S. Dealers Only - Training courses (including Tech Assists, Emerging Issues, Web, IDL and Hands-on) are available through the GM Training website. Refer to Resources and then Training Materials for a complete list of available courses. Canadian Dealers Only - Refer to the Training section of GM infoNet for a complete list of available courses and a copy of the J 38125 Terminal Repair Kit Instruction Manual. Wiring repair information is also available in Service Information (SI). The Wiring Repair section contains information for the following types of wiring repairs: - Testing for intermittent conditions and poor conditions - Flat wire repairs - GMLAN wiring repairs - High temperature wiring repairs - Splicing copper wire using splice clips - Splicing copper wire using splice sleeves - Splicing twisted or shielded cable - Splicing inline harness diodes Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Power and Ground Distribution > Wiring Harness > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wiring Harness: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair > Page 7441 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > Customer Interest: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening Alignment: Customer Interest Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Important: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > Customer Interest: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 7451 Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > Customer Interest: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 7452 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications Alignment: All Technical Service Bulletins Steering/Suspension - Wheel Alignment Specifications WARRANTY ADMINISTRATION Bulletin No.: 05-03-07-009C Date: December 09, 2010 Subject: Wheel Alignment Specifications, Requirements and Recommendations for GM Vehicles Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks Supercede: This bulletin is being extensively revised to provide technicians and warranty administrators with an all inclusive guide for wheel alignments. PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. Please discard Corporate Bulletin Number 05-03-07-009B (Section 03 - Suspension). Purpose The purpose of this bulletin is to provide retail, wholesale and fleet personnel with General Motors' warranty service requirements and recommendations for customer concerns related to wheel alignment. For your convenience, this bulletin updates and centralizes all of GM's Standard Wheel Alignment Service Procedures, Policy Guidelines and bulletins on wheel alignment warranty service. Important PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. The following five (5) key steps are a summary of this bulletin and are REQUIRED in completing a successful wheel alignment service. 1. Verify the vehicle is in an Original Equipment condition for curb weight, tires, wheels, suspension and steering configurations. Vehicles modified in any of these areas are not covered for wheel alignment warranty. 2. Review the customer concern relative to "Normal Operation" definitions. 3. Verify that vehicle is within the "Mileage Policy" range. 4. Document wheel alignment warranty claims appropriately for labor operations E2000 and E2020. The following information must be documented or attached to the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 5. Use the proper wheel alignment equipment (preferred with print-out capability), process and the appropriate calibration maintenance schedules. Important If it is determined that a wheel alignment is necessary under warranty, use the proper labor code for the repair. E2000 for Steering Wheel Angle and/or Front Toe set or E2020 for Wheel Alignment Check/Adjust includes Caster, Camber and Toe set (Wheel alignment labor time for other component repairs is to be charged to the component that causes a wheel alignment operation.). The following flowchart is to help summarize the information detailed in this bulletin and should be used whenever a wheel alignment is performed. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7458 Verify Original Equipment Condition of the Vehicle - Verify that Original Equipment Tires and Wheels or Official GM Accessory Tires and Wheels are on the vehicle. - Verify that aftermarket suspension "Lift" or "Lowering" Kits or other suspension alterations have NOT been done to the vehicle. - Check for accidental damage to the vehicle; for example, severe pothole or curb impacts, collision damage that may have affected the wheel alignment of the vehicle; e.g., engine cradles, suspension control arms, axles, wheels, wheel covers, tires may show evidence of damage/impact. - Check to be sure vehicle has seen "Normal Use" rather than abuse; e.g., very aggressive driving may show up by looking at the tires and condition of the vehicle. - Check for other additional equipment items that may significantly affect vehicle mass such as large tool boxes, campers, snow plow packages (without the snowplow RPO), etc., especially in trucks and cutaway/incomplete vehicles. Significant additional mass can affect trim height and wheel alignment of the vehicle and may necessitate a customer pay wheel alignment when placed semi-permanently in the vehicle (Upfitter instructions are to realign the vehicle after placement of these types of items. (This typically applies to trucks and incomplete vehicles that can be upfit with equipment such as the above.) Customer Concerns, "Normal Operation" Conditions and "Mileage Policy" Possible Concerns The following are typical conditions that may require wheel alignment warranty service: 1. Lead/Pull: defined as "at a constant highway speed on a typical straight road, the amount of effort required at the steering wheel to maintain the vehicle's straight heading." Important Please evaluate for the condition with hands-on the steering wheel. Follow the "Vehicle Leads/Pulls" diagnostic tree located in SI to determine the cause of a lead/pull concern. Lead/Pull concerns can be due to road crown or road slope, tires, wheel alignment or even in rare circumstances a steering gear issue. Lead/pull concerns due to road crown are considered "Normal Operation" and are NOT a warrantable condition -- the customer should be advised that this is "Normal Operation." Important Some customers may comment on a "Lead/Pull" when they hold the steering wheel in a level condition. If so, this is more likely a "steering wheel angle" concern because the customer is "steering" the vehicle to obtain a "level" steering wheel. 2. Steering wheel angle to the left or right (counter-clockwise or clockwise, respectively): Defined as the steering wheel angle (clocking) deviation from "level" while maintaining a straight heading on a typical straight road. 3. Irregular or Premature tire wear: Slight to very slight "feathering" or "edge" wear on the shoulders of tires is NOT considered unusual and should even out with a tire rotation; if the customer is concerned about a "feathering" condition of the tires, the customer could be advised to rotate the tires earlier than the next scheduled mileage/maintenance interval (but no later than the next interval). Be sure to understand the customer's driving habits as this will also heavily influence the tire wear performance; tire wear from aggressive or abusive driving habits is NOT a warrantable condition. Important Slight or mild feathering, cupping, edge or heel/toe wear of tire tread shoulders is "normal" and can show up very early in a tire/vehicle service mileage; in fact, some new tires can show evidence of feathering from the factory. These issues do NOT affect the overall performance and tread life of the tire. Dealer personnel should always check the customer's maintenance records to ensure that tire inflation pressure is being maintained to placard and that the tires are being rotated (modified-X pattern) at the proper mileage intervals. Wheel alignments are NOT to be performed for the types of "Normal" Tire Feathering shown in Figures 1-4 below. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7459 Figure 1: Full Tread View - "NORMAL" Tire "Feathering" Wear on the Shoulder/Adjacent/Center Ribs Figure 2: Tire Shoulder View Example 1 - "NORMAL" Tire "Feathering" Wear on the Shoulder Figure 3: Tire Shoulder View Example 2 - "NORMAL" Tire "Feathering" Wear Figure 4: Detail Side View of Tire Shoulder Area - "NORMAL" Tire "Feathering" Wear Important When a wheel alignment is deemed necessary for tire wear, be sure to document on the repair order, in as much detail as possible, the severity and type of tire wear (e.g., severe center wear or severe inside or outside shoulder wear) and the position of the tire on the vehicle (RF, LF, LR, RR). Please note the customer's concern with the wear such as, noise, appearance, wear life, etc. A field product report with pictures of the tire wear condition is recommended. Refer to Corporate Bulletin Number 02-00-89-002J and #07-00-89-036C. 4. Other repairs that affect wheel alignment; e.g., certain component replacement such as suspension control arm replacement, engine cradle adjustment/replace, steering gear replacement, steering tie rod replace, suspension strut/shock, steering knuckle, etc. may require a wheel alignment. Important If other components or repairs are identified as affecting the wheel alignment, policy calls for the wheel alignment labor time to be charged to the replaced/repaired component's labor operation time rather than the wheel alignment labor operations. Important Vibration type customer concerns are generally NOT due to wheel alignment except in the rare cases; e.g., extreme diagonal wear across the tread. In general, wheel alignments are NOT to be performed as an investigation/correction for vibration concerns. "Normal Operation" Conditions Vehicle Lead/Pull Due to Road Crown or Slope: As part of "Normal Operation," vehicles will follow side-to-side or left to right road crown or slope. Be sure to verify from the customer the types of roads they are driving as they may not recognize the influence of road crown on vehicle lead/pull and steering wheel angle. If a vehicle requires significant steering effort to prevent it from "climbing" the road crown there may be an issue to be looked into further. Important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7460 A wheel alignment will generally NOT correct vehicles that follow the road crown since this is within "Normal Operation." Mileage Policy The following mileage policy applies for E2020 and E2000 labor operations: Note Wheel Alignment is NOT covered under the New Vehicle Limited Warranty for Express and Savana Cutaway vehicles as these vehicles require Upfitters to set the wheel alignment after completing the vehicles. - 0-800 km (0-500 mi): E2000/E2020 claims ONLY allowed with Call Center Authorization. Due to the tie down during shipping, the vehicle's suspension requires some time to reach normal operating position. For this reason, new vehicles are generally NOT to be aligned until they have accumulated at least 800 km (500 mi). A field product report should accompany any claim within this mileage range. - 801-12,000 km (501-7,500 mi): - If a vehicle came from the factory with incorrect alignment settings, any resulting off-angle steering wheel, lead/pull characteristics or the rare occurrence of excessive tire wear would be apparent early in the life of the vehicle. The following policy applies: - Vehicles 100% Factory Set/Measured for Caster/Camber/Toe - Escalade/ESV/EXT, Tahoe/Suburban, Yukon/XL/Denali, Silverado/Sierra, Express/Savana, Corvette and Colorado/Canyon: E2000/E2020 Claims: Call Center Authorization Required - All Vehicles NOT 100% Factory Set/Measured for Caster/Camber/Toe as noted above: E2000/E2020 Claims: Dealer Service Manager Authorization Required - 12,001 km and beyond (7,501 miles and beyond): During this period, customers are responsible for the wheel alignment expense or dealers may provide on a case-by case basis a one-time customer enthusiasm claim up to 16,000 km (10,000 mi). In the event that a defective component required the use of the subject labor operations, the identified defective component labor operation will include the appropriate labor time for a wheel alignment as an add condition to the component repair. Important Only one wheel alignment labor operation claim (E2000 or E2020) may be used per VIN. Warranty Documentation Requirements When a wheel alignment service has been deemed necessary, the following items will need to be clearly documented on/with the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 1. Document the customer concern in as much detail as possible on the repair order and in the warranty administration system. Preferred examples: - Steering wheel is off angle in the counterclockwise direction by approximately x degrees or clocking position. - Vehicle lead/pulls to the right at approximately x-y mph. Vehicle will climb the road crown. Severe, Moderate or Slight. - RF and LF tires are wearing on the outside shoulders with severe feathering. Important In the event of a lead/pull or steering wheel angle concern, please note the direction of lead/pull (left or right) or direction of steering wheel angle (clockwise or counterclockwise) on the repair order and within the warranty claim verbatim. Important In the event of a tire wear concern, please note the position on the vehicle and where the wear is occurring on the tire; i.e., the RF tire is wearing on the inside shoulder. 2. Document the technician's findings on cause and correction of the issue. Examples: - Reset LF toe from 0.45 degrees to 0.10 degrees and RF toe from -0.25 degrees to 0.10 degrees to correct the steering wheel angle from 5 degrees counterclockwise to 0 degrees. - Reset LF camber from 0.25 degrees to -0.05 degrees to correct the cross-camber condition of +0.30 degrees to 0.00 degrees on the vehicle. - Front Sum toe was found to be 0.50 degrees, reset to 0.20 degrees. 3. Print-out the "Before" and "After" wheel alignment measurements/settings and attach them to the Repair Order or if print-out capability is not Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7461 available, measurements may also be clearly and legibly handwritten into the Wheel Alignment Repair Order Questionnaire attached to this bulletin. 4. Attach the Wheel Alignment Repair Order Questionnaire below along with the print-out of "Before" and "After" wheel alignment measurements to the Repair Order and retain for use by GM. Wheel Alignment Equipment and Process Wheel alignments must be performed with a quality machine that will give accurate results when performing checks. "External Reference" (image-based camera technology) is preferred. Please refer to Corporate Bulletin Number 05-00-89-029B: General Motors Dealership Critical Equipment Requirements and Recommendations. Requirements: - Computerized four wheel alignment system. - Computer capable of printing before and after alignment reports. - Computer capable of time and date stamp printout. - Racking system must have jacking capability - Racking system must be capable of level to 1.6 mm (1/16 in) - Appropriate wheel stops and safety certification - Built-in turn plates and slip plates - Wheel clamps capable of attaching to 20" or larger wheels - Racking capable of accepting any GM passenger car or light duty truck - Operator properly trained and ASE-certified (U.S. only) in wheel alignment Recommendations: Racking should have front and rear jacking capability. Equipment Maintenance and Calibration: Alignment machines must be regularly calibrated in order to give correct information. Most manufacturers recommend the following: - Alignment machines with "internal reference" sensors should be checked (and calibrated, if necessary) every six months. - Alignment machines with "external reference" (image-based camera technology) should be checked (and calibrated, if necessary) once a year. - Racks must be kept level to within 1.6 mm (1/16 in). - If any instrument that is part of the alignment machine is dropped or damaged in some way, check the calibration immediately. Check with the manufacturer of your specific equipment for their recommended service/calibration schedule. Wheel Alignment Process When performing wheel alignment measurement and/or adjustment, the following steps should be taken: Preliminary Steps: 1. Verify that the vehicle has a full tank of fuel (compensate as necessary). 2. Inspect the wheels and the tires for damage. 3. Inspect the tires for the proper inflation and irregular tire wear. 4. Inspect the wheel bearings for excessive play. 5. Inspect all suspension and steering parts for looseness, wear, or damage. 6. Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components. 7. Inspect the vehicle trim height. 8. Compensate for frame angle on targeted vehicles (refer to Wheel Alignment Specifications in SI). Satisfactory vehicle operation may occur over a wide range of alignment angles. However, if the wheel alignment angles are not within the range of specifications, adjust the wheel alignment to the specifications. Refer to Wheel Alignment Specifications in SI. Give consideration to excess loads, such as tool boxes, sample cases, etc. Follow the wheel alignment equipment manufacturer's instructions. Measure/Adjust: Important Prior to making any adjustments to wheel alignment on a vehicle, technicians must verify that the wheel alignment specifications loaded into their wheel alignment machine are up-to-date by comparing these to the wheel alignment specifications for the appropriate model and model year in SI. Using incorrect and/or outdated specifications may result in unnecessary adjustments, irregular and/or premature tire wear and repeat customer concerns Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7462 Important When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front wheel alignment angles. Perform the following steps in order to measure the front and rear alignment angles: 1. Install the alignment equipment according to the manufacturer's instructions. 2. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment. 3. Measure the alignment angles and record the readings. If necessary, adjust the wheel alignment to vehicle specification and record the before and after measurements. Refer to Wheel Alignment Specifications in SI. Important Technicians must refer to SI for the correct wheel alignment specifications. SI is the only source of GM wheel alignment specifications that is kept up-to-date throughout the year. Test drive vehicle to ensure proper repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7463 Frame Angle Measurement (Express / Savana Only) ........ Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7464 What corrected the customer concern and was the repair verified? Please Explain: ............. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening Alignment: All Technical Service Bulletins Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Important: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 7469 Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Technical Service Bulletins for Alignment: > 533403 > May > 95 > Rear Wheel - Tire Position in Wheel Well Opening > Page 7470 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications Alignment: All Technical Service Bulletins Steering/Suspension - Wheel Alignment Specifications WARRANTY ADMINISTRATION Bulletin No.: 05-03-07-009C Date: December 09, 2010 Subject: Wheel Alignment Specifications, Requirements and Recommendations for GM Vehicles Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks Supercede: This bulletin is being extensively revised to provide technicians and warranty administrators with an all inclusive guide for wheel alignments. PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. Please discard Corporate Bulletin Number 05-03-07-009B (Section 03 - Suspension). Purpose The purpose of this bulletin is to provide retail, wholesale and fleet personnel with General Motors' warranty service requirements and recommendations for customer concerns related to wheel alignment. For your convenience, this bulletin updates and centralizes all of GM's Standard Wheel Alignment Service Procedures, Policy Guidelines and bulletins on wheel alignment warranty service. Important PLEASE FAMILIARIZE YOURSELF WITH THESE UPDATES BEFORE PERFORMING YOUR NEXT GM WHEEL ALIGNMENT SERVICE. The following five (5) key steps are a summary of this bulletin and are REQUIRED in completing a successful wheel alignment service. 1. Verify the vehicle is in an Original Equipment condition for curb weight, tires, wheels, suspension and steering configurations. Vehicles modified in any of these areas are not covered for wheel alignment warranty. 2. Review the customer concern relative to "Normal Operation" definitions. 3. Verify that vehicle is within the "Mileage Policy" range. 4. Document wheel alignment warranty claims appropriately for labor operations E2000 and E2020. The following information must be documented or attached to the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 5. Use the proper wheel alignment equipment (preferred with print-out capability), process and the appropriate calibration maintenance schedules. Important If it is determined that a wheel alignment is necessary under warranty, use the proper labor code for the repair. E2000 for Steering Wheel Angle and/or Front Toe set or E2020 for Wheel Alignment Check/Adjust includes Caster, Camber and Toe set (Wheel alignment labor time for other component repairs is to be charged to the component that causes a wheel alignment operation.). The following flowchart is to help summarize the information detailed in this bulletin and should be used whenever a wheel alignment is performed. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7476 Verify Original Equipment Condition of the Vehicle - Verify that Original Equipment Tires and Wheels or Official GM Accessory Tires and Wheels are on the vehicle. - Verify that aftermarket suspension "Lift" or "Lowering" Kits or other suspension alterations have NOT been done to the vehicle. - Check for accidental damage to the vehicle; for example, severe pothole or curb impacts, collision damage that may have affected the wheel alignment of the vehicle; e.g., engine cradles, suspension control arms, axles, wheels, wheel covers, tires may show evidence of damage/impact. - Check to be sure vehicle has seen "Normal Use" rather than abuse; e.g., very aggressive driving may show up by looking at the tires and condition of the vehicle. - Check for other additional equipment items that may significantly affect vehicle mass such as large tool boxes, campers, snow plow packages (without the snowplow RPO), etc., especially in trucks and cutaway/incomplete vehicles. Significant additional mass can affect trim height and wheel alignment of the vehicle and may necessitate a customer pay wheel alignment when placed semi-permanently in the vehicle (Upfitter instructions are to realign the vehicle after placement of these types of items. (This typically applies to trucks and incomplete vehicles that can be upfit with equipment such as the above.) Customer Concerns, "Normal Operation" Conditions and "Mileage Policy" Possible Concerns The following are typical conditions that may require wheel alignment warranty service: 1. Lead/Pull: defined as "at a constant highway speed on a typical straight road, the amount of effort required at the steering wheel to maintain the vehicle's straight heading." Important Please evaluate for the condition with hands-on the steering wheel. Follow the "Vehicle Leads/Pulls" diagnostic tree located in SI to determine the cause of a lead/pull concern. Lead/Pull concerns can be due to road crown or road slope, tires, wheel alignment or even in rare circumstances a steering gear issue. Lead/pull concerns due to road crown are considered "Normal Operation" and are NOT a warrantable condition -- the customer should be advised that this is "Normal Operation." Important Some customers may comment on a "Lead/Pull" when they hold the steering wheel in a level condition. If so, this is more likely a "steering wheel angle" concern because the customer is "steering" the vehicle to obtain a "level" steering wheel. 2. Steering wheel angle to the left or right (counter-clockwise or clockwise, respectively): Defined as the steering wheel angle (clocking) deviation from "level" while maintaining a straight heading on a typical straight road. 3. Irregular or Premature tire wear: Slight to very slight "feathering" or "edge" wear on the shoulders of tires is NOT considered unusual and should even out with a tire rotation; if the customer is concerned about a "feathering" condition of the tires, the customer could be advised to rotate the tires earlier than the next scheduled mileage/maintenance interval (but no later than the next interval). Be sure to understand the customer's driving habits as this will also heavily influence the tire wear performance; tire wear from aggressive or abusive driving habits is NOT a warrantable condition. Important Slight or mild feathering, cupping, edge or heel/toe wear of tire tread shoulders is "normal" and can show up very early in a tire/vehicle service mileage; in fact, some new tires can show evidence of feathering from the factory. These issues do NOT affect the overall performance and tread life of the tire. Dealer personnel should always check the customer's maintenance records to ensure that tire inflation pressure is being maintained to placard and that the tires are being rotated (modified-X pattern) at the proper mileage intervals. Wheel alignments are NOT to be performed for the types of "Normal" Tire Feathering shown in Figures 1-4 below. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7477 Figure 1: Full Tread View - "NORMAL" Tire "Feathering" Wear on the Shoulder/Adjacent/Center Ribs Figure 2: Tire Shoulder View Example 1 - "NORMAL" Tire "Feathering" Wear on the Shoulder Figure 3: Tire Shoulder View Example 2 - "NORMAL" Tire "Feathering" Wear Figure 4: Detail Side View of Tire Shoulder Area - "NORMAL" Tire "Feathering" Wear Important When a wheel alignment is deemed necessary for tire wear, be sure to document on the repair order, in as much detail as possible, the severity and type of tire wear (e.g., severe center wear or severe inside or outside shoulder wear) and the position of the tire on the vehicle (RF, LF, LR, RR). Please note the customer's concern with the wear such as, noise, appearance, wear life, etc. A field product report with pictures of the tire wear condition is recommended. Refer to Corporate Bulletin Number 02-00-89-002J and #07-00-89-036C. 4. Other repairs that affect wheel alignment; e.g., certain component replacement such as suspension control arm replacement, engine cradle adjustment/replace, steering gear replacement, steering tie rod replace, suspension strut/shock, steering knuckle, etc. may require a wheel alignment. Important If other components or repairs are identified as affecting the wheel alignment, policy calls for the wheel alignment labor time to be charged to the replaced/repaired component's labor operation time rather than the wheel alignment labor operations. Important Vibration type customer concerns are generally NOT due to wheel alignment except in the rare cases; e.g., extreme diagonal wear across the tread. In general, wheel alignments are NOT to be performed as an investigation/correction for vibration concerns. "Normal Operation" Conditions Vehicle Lead/Pull Due to Road Crown or Slope: As part of "Normal Operation," vehicles will follow side-to-side or left to right road crown or slope. Be sure to verify from the customer the types of roads they are driving as they may not recognize the influence of road crown on vehicle lead/pull and steering wheel angle. If a vehicle requires significant steering effort to prevent it from "climbing" the road crown there may be an issue to be looked into further. Important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7478 A wheel alignment will generally NOT correct vehicles that follow the road crown since this is within "Normal Operation." Mileage Policy The following mileage policy applies for E2020 and E2000 labor operations: Note Wheel Alignment is NOT covered under the New Vehicle Limited Warranty for Express and Savana Cutaway vehicles as these vehicles require Upfitters to set the wheel alignment after completing the vehicles. - 0-800 km (0-500 mi): E2000/E2020 claims ONLY allowed with Call Center Authorization. Due to the tie down during shipping, the vehicle's suspension requires some time to reach normal operating position. For this reason, new vehicles are generally NOT to be aligned until they have accumulated at least 800 km (500 mi). A field product report should accompany any claim within this mileage range. - 801-12,000 km (501-7,500 mi): - If a vehicle came from the factory with incorrect alignment settings, any resulting off-angle steering wheel, lead/pull characteristics or the rare occurrence of excessive tire wear would be apparent early in the life of the vehicle. The following policy applies: - Vehicles 100% Factory Set/Measured for Caster/Camber/Toe - Escalade/ESV/EXT, Tahoe/Suburban, Yukon/XL/Denali, Silverado/Sierra, Express/Savana, Corvette and Colorado/Canyon: E2000/E2020 Claims: Call Center Authorization Required - All Vehicles NOT 100% Factory Set/Measured for Caster/Camber/Toe as noted above: E2000/E2020 Claims: Dealer Service Manager Authorization Required - 12,001 km and beyond (7,501 miles and beyond): During this period, customers are responsible for the wheel alignment expense or dealers may provide on a case-by case basis a one-time customer enthusiasm claim up to 16,000 km (10,000 mi). In the event that a defective component required the use of the subject labor operations, the identified defective component labor operation will include the appropriate labor time for a wheel alignment as an add condition to the component repair. Important Only one wheel alignment labor operation claim (E2000 or E2020) may be used per VIN. Warranty Documentation Requirements When a wheel alignment service has been deemed necessary, the following items will need to be clearly documented on/with the repair order: - Customer concern in detail - What corrected the customer concern? - If a wheel alignment is performed: - Consult SI for proper specifications. - Document the "Before" AND "After" wheel alignment measurements/settings. - Completed "Wheel Alignment Repair Order Questionnaire" (form attached to this bulletin) 1. Document the customer concern in as much detail as possible on the repair order and in the warranty administration system. Preferred examples: - Steering wheel is off angle in the counterclockwise direction by approximately x degrees or clocking position. - Vehicle lead/pulls to the right at approximately x-y mph. Vehicle will climb the road crown. Severe, Moderate or Slight. - RF and LF tires are wearing on the outside shoulders with severe feathering. Important In the event of a lead/pull or steering wheel angle concern, please note the direction of lead/pull (left or right) or direction of steering wheel angle (clockwise or counterclockwise) on the repair order and within the warranty claim verbatim. Important In the event of a tire wear concern, please note the position on the vehicle and where the wear is occurring on the tire; i.e., the RF tire is wearing on the inside shoulder. 2. Document the technician's findings on cause and correction of the issue. Examples: - Reset LF toe from 0.45 degrees to 0.10 degrees and RF toe from -0.25 degrees to 0.10 degrees to correct the steering wheel angle from 5 degrees counterclockwise to 0 degrees. - Reset LF camber from 0.25 degrees to -0.05 degrees to correct the cross-camber condition of +0.30 degrees to 0.00 degrees on the vehicle. - Front Sum toe was found to be 0.50 degrees, reset to 0.20 degrees. 3. Print-out the "Before" and "After" wheel alignment measurements/settings and attach them to the Repair Order or if print-out capability is not Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7479 available, measurements may also be clearly and legibly handwritten into the Wheel Alignment Repair Order Questionnaire attached to this bulletin. 4. Attach the Wheel Alignment Repair Order Questionnaire below along with the print-out of "Before" and "After" wheel alignment measurements to the Repair Order and retain for use by GM. Wheel Alignment Equipment and Process Wheel alignments must be performed with a quality machine that will give accurate results when performing checks. "External Reference" (image-based camera technology) is preferred. Please refer to Corporate Bulletin Number 05-00-89-029B: General Motors Dealership Critical Equipment Requirements and Recommendations. Requirements: - Computerized four wheel alignment system. - Computer capable of printing before and after alignment reports. - Computer capable of time and date stamp printout. - Racking system must have jacking capability - Racking system must be capable of level to 1.6 mm (1/16 in) - Appropriate wheel stops and safety certification - Built-in turn plates and slip plates - Wheel clamps capable of attaching to 20" or larger wheels - Racking capable of accepting any GM passenger car or light duty truck - Operator properly trained and ASE-certified (U.S. only) in wheel alignment Recommendations: Racking should have front and rear jacking capability. Equipment Maintenance and Calibration: Alignment machines must be regularly calibrated in order to give correct information. Most manufacturers recommend the following: - Alignment machines with "internal reference" sensors should be checked (and calibrated, if necessary) every six months. - Alignment machines with "external reference" (image-based camera technology) should be checked (and calibrated, if necessary) once a year. - Racks must be kept level to within 1.6 mm (1/16 in). - If any instrument that is part of the alignment machine is dropped or damaged in some way, check the calibration immediately. Check with the manufacturer of your specific equipment for their recommended service/calibration schedule. Wheel Alignment Process When performing wheel alignment measurement and/or adjustment, the following steps should be taken: Preliminary Steps: 1. Verify that the vehicle has a full tank of fuel (compensate as necessary). 2. Inspect the wheels and the tires for damage. 3. Inspect the tires for the proper inflation and irregular tire wear. 4. Inspect the wheel bearings for excessive play. 5. Inspect all suspension and steering parts for looseness, wear, or damage. 6. Inspect the steering wheel for excessive drag or poor return due to stiff or rusted linkage or suspension components. 7. Inspect the vehicle trim height. 8. Compensate for frame angle on targeted vehicles (refer to Wheel Alignment Specifications in SI). Satisfactory vehicle operation may occur over a wide range of alignment angles. However, if the wheel alignment angles are not within the range of specifications, adjust the wheel alignment to the specifications. Refer to Wheel Alignment Specifications in SI. Give consideration to excess loads, such as tool boxes, sample cases, etc. Follow the wheel alignment equipment manufacturer's instructions. Measure/Adjust: Important Prior to making any adjustments to wheel alignment on a vehicle, technicians must verify that the wheel alignment specifications loaded into their wheel alignment machine are up-to-date by comparing these to the wheel alignment specifications for the appropriate model and model year in SI. Using incorrect and/or outdated specifications may result in unnecessary adjustments, irregular and/or premature tire wear and repeat customer concerns Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7480 Important When performing adjustments to vehicles requiring a 4-wheel alignment, set the rear wheel alignment angles first in order to obtain proper front wheel alignment angles. Perform the following steps in order to measure the front and rear alignment angles: 1. Install the alignment equipment according to the manufacturer's instructions. 2. Jounce the front and the rear bumpers 3 times prior to checking the wheel alignment. 3. Measure the alignment angles and record the readings. If necessary, adjust the wheel alignment to vehicle specification and record the before and after measurements. Refer to Wheel Alignment Specifications in SI. Important Technicians must refer to SI for the correct wheel alignment specifications. SI is the only source of GM wheel alignment specifications that is kept up-to-date throughout the year. Test drive vehicle to ensure proper repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7481 Frame Angle Measurement (Express / Savana Only) ........ Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > 05-03-07-009C > Dec > 10 > Steering/Suspension - Wheel Alignment Specifications > Page 7482 What corrected the customer concern and was the repair verified? Please Explain: ............. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 7483 Alignment: By Symptom Technical Service Bulletin # 533403 Date: 950501 Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 7484 Important: Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 7485 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 7486 Technical Service Bulletin # 533403 Date: 950501 Rear Wheel - Tire Position in Wheel Well Opening FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-34-03 DATE: May, 1995 SUBJECT: Rear Wheel/Tire Position in Wheel Well Opening (Elongate Axle Bracket Control Arm Attaching Bolt Holes) MODELS: 1994-95 Chevrolet Caprice/Impala SS CONDITION Some customers may comment that one rear wheel may appear more forward in wheel well opening than wheel on opposite side of vehicle or that vehicle appears to dog track when viewed from the rear when in operation. CAUSE Rear lower control arm frame bracket holes pierced off location during frame manufacturing. CORRECTION Elongate holes in rear axle control arm bracket per service procedure indicated below: 1. Raise vehicle and support rear axle to simulate curb height position (weight of vehicle on axle). 2. Using lower edge of sill plate as a guide for scale/ruler, measure distance from tire to wheel well opening on both sides of vehicle (Reference Figure 1). 3. Subtract smaller dimension from larger one and refer to chart below to determine amount holes of axle lower control arm bracket are to be elongated. Side to Side Dimension Hole Elongation Difference Amount 5 mm through 10 mm 4 mm 11 mm through 15 mm 6 mm 16 mm through 20 mm 8 mm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 7487 Important: Holes to be elongated in a forward direction are those on the rear axle lower control arm bracket, on the side of the vehicle that had the smaller dimension measured in Step 2. 4. Disconnect and remove rear stabilizer shaft, if equipped. 5. Remove lower control arm to axle assembly attaching bolt and swing control arm downward on side of axle determined in Step 3 to require hole elongation. 6. Cut out template along outer outline. Cut out hole in template indicated as original bracket hole. (Reference Figure 5). 7. Position template on inboard surface of axle control arm bracket as shown in Figure 2. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 8. Transfer from the template to the bracket the amount hole is to be elongated along axis indicated on template. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Technical Service Bulletins > All Other Service Bulletins for Alignment: > Page 7488 9. Position template on outboard surface of axle control arm bracket as shown in Figure 3. Align hole in template with hole in bracket and insure bottom edge of template is parallel to bottom edge of bracket. 10. Repeat step 8. 11. Using a die grinder or other suitable tool, elongate holes. 12. Swing lower control arm into position and install attaching bolt and nut as shown in Figure 4. With axle assembly positioned as far rearward as elongated holes will allow, torque attaching bolt to 190 Nm (140 lb.ft.) holding nut with a backup wrench. 13. Position and connect stabilizer shaft and torque attaching bolts to 85 Nm (63 lb.ft.). 14. Lower vehicle. WARRANTY INFORMATION For vehicles repaired under warranty, use: Labor Operation Labor Time E5610 Use Published Labor Operation Time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Specifications > Vehicle Ride (Trim) Height Specifications Alignment: Specifications Vehicle Ride (Trim) Height Specifications Fig. 4 Vehicle Ride Height Measurement Locations & Specifications Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Specifications > Vehicle Ride (Trim) Height Specifications > Page 7491 Alignment: Specifications Alignment Specifications Front Alignment Specifications Caster Angle, Degrees Limits ................................................................................................................................................... ....................................................................... [01] Desired ................................................................. ....................................................................................................................................................... [03] Camber Angle, Degrees Limits ................................................................................................................................................... ................................................................ - 1 to +1 Desired ................................................................. ........................................................................................................................................................... 0 Total Toe, Degrees .............................................................................................................................. ............................................................... -.04 to +.36 Ball Joint Wear, Inch Lower Ball Stud [02] ............................................................................................................................ ..................................................................... .050 Upper Ball Stud [02] .............................................. ................................................................................................................................................... .125 [01] Left side, +2.25 to +4.25; right side, +2.75 to +4.75. [02] Refer to Suspension/Ball Joint, lower or Upper/Service and Repair for proper ball joint inspection procedure. [03] Left side, +3.25; right side, +3.75. Rear Alignment Specifications Thrust Angle, Degrees ......................................................................................................................... .............................................................. -.15 to +.15 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Service and Repair > Preliminary Inspection Alignment: Service and Repair Preliminary Inspection 1. Inspect tires for proper inflation and similar tread wear. 2. Inspect hub and bearing for excessive wear, repair as required. 3. Inspect ball joints. 4. Inspect tie rod ends for excessive looseness. 5. Check wheel and tire runout. 6. Inspect vehicle ride height. 7. Inspect rack and pinion for looseness at frame. 8. Ensure proper strut operation. 9. Check suspension and steering components for damage, replace as required. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Service and Repair > Preliminary Inspection > Page 7494 Alignment: Service and Repair Ride/Trim Height Measurement and Adjustment Fig. 4 Vehicle Ride Height Measurement Locations & Specifications Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Service and Repair > Preliminary Inspection > Page 7495 Alignment: Service and Repair Front Wheel Alignment Front Caster Adjustment Fig. 1 Caster & Camber Adjustments Caster adjustments are made by means of shims between the upper control arm inner support shaft and the support bracket attached to the frame, Fig. 1. Shims may be added, subtracted or transferred to change the readings. Transfer shims from front to rear or rear to front. The transfer of one shim to the front bolt from the rear bolt will decrease positive caster. One shim (1/32 inch) transferred from the rear bolt to the front bolt will change caster about 1/2 degree. Front Camber Adjustment Fig. 1 Caster & Camber Adjustments Camber adjustments are made by means of shims between the upper control arm inner support shaft and the support bracket attached to the frame, Fig. 1. Shims may be added, subtracted or transferred to change the readings. Change shims at both the front and rear of the shaft. Adding an equal number of shims at both front and rear of the support shaft will decrease positive camber. One shim (1/32 inch) at each location will move camber approximately 1/6 degree. Front Toe Adjustment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Alignment > System Information > Service and Repair > Preliminary Inspection > Page 7496 Fig. 2 Toe-in Adjustment Toe-in can be adjusted by loosening the clamp bolts at each end of each tie rod and turning each tie rod to increase or decrease its length as necessary until proper toe-in is secured and the steering gear is on the high point for straight-ahead driving, Fig. 2. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Relays and Modules - Steering and Suspension > Relays and Modules - Steering > Steering Control Module > Component Information > Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Relays and Modules - Steering and Suspension > Relays and Modules - Steering > Steering Control Module > Component Information > Locations > Page 7502 Power Steering Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Relays and Modules - Steering and Suspension > Relays and Modules - Suspension > Compressor/Pump Relay, Suspension Control > Component Information > Description and Operation Compressor/Pump Relay: Description and Operation DESCRIPTION The compressor relay is controlled by the height sensor and completes the 12-volt circuit to the compressor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Locations Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions Power Steering Pressure Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7514 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7515 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7516 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7517 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7518 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7519 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7520 Power Steering Pressure Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7521 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7522 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7523 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7524 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7525 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7526 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7527 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7528 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7529 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7530 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7531 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7532 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7533 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7534 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7535 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7536 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7537 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7538 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7539 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7540 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7541 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7542 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7543 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7544 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7545 Power Steering Pressure Switch Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Page 7546 Power Steering Pressure Switch: Description and Operation This switch informs the PCM when the power steering pressure is high. During high pressure conditions, the Powertrain Control Module (PCM) will increase idle speed to compensate for the additional load. When the switch closes, the PCM will increase idle speed to compensate for the additional load. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations Center Of Rear Crossmember Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7551 Ride Height Sensor: Description and Operation DESCRIPTION The height sensor controls two circuits, compressor relay coil ground circuit and exhaust solenoid coil ground circuit. To prevent energizing the compressor relay and exhaust solenoid circuits during normal ride motions, the sensor circuit provides a predetermined delay before the ground circuit is completed. The sensor electronically limits compressor run time and exhaust solenoid energized time. This limit function is necessary to prevent continuous compressor operation in case of a system leak or continuous exhaust solenoid operation. This timer is reset whenever the ignition is turned Off and On, or height sensor exhaust or compressor signal changes. The height sensor is mounted to the body frame in the rear of the vehicle. The sensor actuator arm is attached to the control arm by a short link Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7552 Ride Height Sensor: Testing and Inspection CAUTION: When diagnostic procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Turn ignition Off, then On. This will reset height sensor timer circuits. 2. Raise vehicle on hoist. Ensure rear wheels or axle housing are supported and that vehicle is at proper trim height. 3. Disconnect link from height sensor arm, then ensure sensor wiring and harness ground are connected properly. 4. Move sensor arm upward. There should be a delay of 8-15 seconds before compressor turns on and shocks start to inflate. As soon as shocks start to fill, stop compressor by moving sensor arm down. 5. Move sensor arm down below position where compressor stopped. There should be a delay of 8-15 seconds before shocks start to deflate and vehicle lowers. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7553 Ride Height Sensor: Adjustments ADJUSTMENTS The link should be properly attached to the sensor arm and track bar, when making this adjustment. 1. Loosen lock bolt securing metal arm to height sensor plastic arm. 2. To raise vehicle trim height, move plastic arm upward and tighten lock bolt. 3. To lower vehicle trim height, loosen lock bolt securing metal arm to height sensor plastic arm, then move plastic arm down. 4. If adjustment cannot be made, check for correct sensor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Sensors and Switches - Steering and Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7554 Ride Height Sensor: Service and Repair WARNING: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Disconnect battery ground cable. 2. Raise and support vehicle. 3. Disconnect harness from sensor electrical connector by squeezing oval sides of the connector lock to release locking tabs. 4. Remove link from height sensor arm, then remove sensor mounting screws or nuts and the sensor. 5. Remove sensor mounting bracket to underbody attaching screws and remove bracket. 6. Reverse procedure to install, noting the following: a. When connecting harness to sensor electrical connector, push connector into sensor plug until sloped shoulder on rear edge of boss is visible in plug slot. Push oval connector lock onto plug until its two locking tabs snap over shoulder of sensor plug. b. Perform height sensor operational check and adjustment procedure as described under Testing and Inspection. See: Testing and Inspection Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Front Steering Knuckle > Component Information > Technical Service Bulletins > Steering Knuckle Nuts - Revised Torque Specification Front Steering Knuckle: Technical Service Bulletins Steering Knuckle Nuts - Revised Torque Specification FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-33-02A DATE: June, 1995 SUBJECT: Section 3C - Revised Torque Specification for Steering Knuckle Nuts (Upper and Lower) MODELS: 1993-95 Buick Roadmaster 1993-95 Cadillac Fleetwood 1993-95 Chevrolet Caprice 1994-95 Chevrolet Impala SS The torque specification for upper and lower steering knuckle nuts should be as follows: Tighten ^ Steering knuckle nut (upper) (1) to 83 Nm (61 lb.ft.), additional tightening may be required to insert cotter pin (3). Do not exceed 60° additional tightening. ^ Steering knuckle nut (lower) (2) to 112 Nm (63 lb.ft.), additional tightening may be required to insert cotter pin (3). Do not exceed 60° additional tightening. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Bleeding > System Information > Service and Repair Power Steering Bleeding: Service and Repair Fig. 12 Power Steering System Bleed Procedure. Bleed power steering system after any component replacement, disconnecting fluid line or in case of steering system noise. Bleed system to prevent pump damage, stop steering noise and to ensure proper system operation. Before bleeding, inspect steering system. Check and correct if needed power steering lines touching frame body or engine. Also check all hose connections for looseness or leaks and tighten. Refer to Fig. 12 for proper bleeding procedure. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Fluid Reservoir > Component Information > Locations Power Steering Fluid Reservoir: Locations Engine Compartment LH Front of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pressure Control Valve > Component Information > Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Locations Component Location - Pictorial View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement Power Steering Pump: Service and Repair Replacement Fig. 14 Exploded View Of Power Steering Pump Mounting Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7575 Fig. 15 Power Steering Gear Inlet & Outlet Hose Locations 1. Siphon power steering fluid from reservoir to prevent excess spillage. 2. Drain engine cooling system into suitable container(s), then, if equipped with mechanical fan, remove engine cooling fan bracket. 3. Disconnect heater inlet and outlet hoses from water pump. 4. Remove heater inlet and outlet hose clip bolt/screw from generator and power steering pump bracket, Fig. 14 then position aside. 5. Remove drive belt from power steering pump. 6. Disconnect power steering gear inlet hose from power steering pump, Fig. 15 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7576 7. Disconnect power steering fluid reservoir hose from power steering pump by squeezing clamp and sliding away from pump, then rotating and sliding hose away from power steering pump, Fig. 15 8. Remove pump bracket bolts/screws and generator bracket bolt/screw, then pump and pulley. 9. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7577 Power Steering Pump: Service and Repair Disassembly/Assembly CB Series Pump Fig. 5 Exploded View Of CB Series Power Steering Pump Fig. 6 Return Tube Removal. CB Series Power Steering Pump Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7578 Fig. 7 Rotor And/Or Pump Ring Installation. CB Series Power Steering Pump DISASSEMBLE 1. Disconnect battery ground cable, then remove power steering pump from vehicle. Refer to individual car chapters for procedures. 2. Remove union fitting with O-ring and the O-ring seal, Fig. 5. 3. Remove control valve assembly and flow control spring. 4. Protect driveshaft with shim stock and remove driveshaft seal by cutting with small chisel. Discard seal. 5. Remove return tube using tap, nut and washers, Fig. 6, as follows. Plug return tube to prevent chips from entering pump. a. Stack five 5/8 inch washers onto return tube. b. Run one 9/16 inch-12 nut midway up a 9/1 inch 12 tap. c. Install threaded end of tap into return tube until nut is positioned against washers. d. Using wrench, hold top stationary while turning nut clockwise. 6. Remove end cover retaining ring by inserting punch in access hole. 7. Gently push on driveshaft to assist in removing end cover, O-ring, pressure plate spring, pump ring, pump vanes and the driveshaft subassembly, consisting of pump rotor, thrust plate, driveshaft and shaft retaining ring. 8. Remove O-ring from housing. 9. Remove dowel pins, then the driveshaft seal if not previously removed. 10. Remove pressure plate, pressure plate spring and O-ring from end cover. 11. Remove shaft retaining ring from driveshaft, then the pump rotor and thrust plate. INSPECTION 1. Clean all parts in power steering fluid, then dry thoroughly. 2. Inspect pump ring, vanes, thrust plate, pressure plate and driveshaft for scoring, pitting or chatter marks, replacing parts as necessary. ASSEMBLE 1. Lubricate new driveshaft seal with power steering fluid and, using seal installer tool No. J 7728, or equivalent, press driveshaft seal into pump housing. 2. Install pump ring dowel pins into housing. 3. Install thrust plate and pump rotor onto driveshaft, Fig. 7. 4. Install new shaft retaining ring onto driveshaft. 5. Install driveshaft subassembly into housing. 6. Install pump ring with holes positioned correctly onto dowel pins, Fig. 7, in housing. 7. Install vanes into pump rotor. 8. Lubricate new O-ring (large) with power steering fluid and install O-ring into end cover. 9. Install pressure plate and pressure plate spring. 10. Lubricate new O-ring (small) and install O-ring into end cover. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7579 11. Lubricate outer edge of end cover with power steering fluid and press end cover into housing. 12. Insert retaining ring into groove in housing, with ring opening near access hole opening. 13. Remove plug and any chips, then coat end of new return tube with Loctite solvent part No. 75559 and Loctite adhesive part No. 290, or equivalents and press return tube into housing until bottomed. P Series L/Reservoir Pump Fig. 9 Power Steering Pump Assembly Overhaul (Part 1 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7580 Fig. 9 Power Steering Pump Assembly Overhaul (Part 2 Of 2) Reverse Rotation Pump Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7581 Fig. 8 Power Steering Pump Assembly Overhaul. Reverse Rotation DISASSEMBLE 1. Disconnect battery ground cable, then remove power steering pump from vehicle. Refer to individual chassis chapter for procedure. 2. Remove retaining ring using punch in access hole, Fig. 8. 3. Remove internal components from pump assembly by gently pushing on driveshaft. Components should include pressure plate and subassembly, consisting of end cover, O-ring seal, pressure plate spring and pressure plate. Driveshaft subassembly, consisting of pump rotor, thrust plate, driveshaft and shaft retaining ring. 4. Remove O-ring from pump housing. 5. Remove dowel pins and driveshaft seal. 6. Remove end cover, pressure plate spring and O-ring from pressure plate. 7. Remove pump ring and vanes from driveshaft subassembly, then shaft retaining rings from driveshaft. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7582 8. Remove thrust plate and pump rotor from driveshaft. INSPECTION 1. Clean all parts in power steering fluid, then dry thoroughly. 2. Inspect pump ring, vanes, thrust plate, pressure plate, rotor and driveshaft for scoring, pitting or chatter marks, replacing parts as necessary. ASSEMBLE 1. Lubricate new driveshaft seal with power steering fluid and, using seal installer tool No. J 7728, or equivalent, press driveshaft seal into pump housing. 2. Install pump ring dowel pins into housing. 3. Install thrust plate and pump rotor onto driveshaft. 4. Install new shaft retaining ring onto driveshaft. 5. Install driveshaft subassembly into housing. 6. Install vanes into pump rotor. 7. Install pump ring, with holes positioned correctly onto dowel pins in housing. 8. Lubricate new O-ring with power steering fluid and install O-ring into groove in pump housing. 9. Install pressure plate and pressure plate spring. 10. Lubricate new O-ring and install O-ring into end cover. 11. Lubricate outer edge of end cover with power steering fluid and press end cover into housing. 12. Insert retaining ring into groove in housing, with ring opening near access hole opening. 13. Remove plug and any chips, then coat end of new return tube with Loctite solvent 75559 and Loctite 290 adhesive, or equivalents, and press return tube into housing until bottomed. TC Series Pump Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7583 Fig. 11 Power Steering Pump Assembly Overhaul (Part 1 Of 4). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7584 Fig. 11 Power Steering Pump Assembly Overhaul (Part 2 Of 4). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7585 Fig. 11 Power Steering Pump Assembly Overhaul (Part 3 Of 4). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Power Steering Pump > Component Information > Service and Repair > Replacement > Page 7586 Fig. 11 Power Steering Pump Assembly Overhaul (Part 4 Of 4). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Steering Control Module > Component Information > Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Power Steering > Steering Control Module > Component Information > Locations > Page 7590 Power Steering Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Relays and Modules - Steering > Steering Control Module > Component Information > Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Relays and Modules - Steering > Steering Control Module > Component Information > Locations > Page 7595 Power Steering Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Locations Left Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions Power Steering Pressure Switch: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7602 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7603 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7604 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7605 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7606 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7607 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7608 Power Steering Pressure Switch: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7609 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7610 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7611 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7612 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7613 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7614 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7615 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7616 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7617 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7618 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7619 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7620 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7621 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7622 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7623 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7624 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7625 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7626 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7627 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7628 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7629 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7630 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7631 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7632 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Diagram Information and Instructions > Page 7633 Power Steering Pressure Switch Circuit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Sensors and Switches - Steering > Power Steering Pressure Switch > Component Information > Diagrams > Page 7634 Power Steering Pressure Switch: Description and Operation This switch informs the PCM when the power steering pressure is high. During high pressure conditions, the Powertrain Control Module (PCM) will increase idle speed to compensate for the additional load. When the switch closes, the PCM will increase idle speed to compensate for the additional load. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Column > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming Air Bag(s) Arming and Disarming: Service and Repair Air Bag Disarming and Arming Disabling the SIR System The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Ensure front wheels are pointed straight ahead. 2. Turn ignition switch to LOCK position and remove SIR or AIR BAG fuse. 3. Remove Connector Position Assurance (CPA), then disconnect both yellow 2-way SIR electrical connectors at base of steering column. 4. Wait at least 2 minutes before proceeding with diagnosis or service. Enabling the SIR System 1. Connect both 2-way yellow connectors at base of steering column. 2. Install Connector Position Assurance (CPA). 3. Install SIR or AIR BAG fuse into fuse block. 4. Turn ignition to the RUN position and ensure that the "Inflatable Restraint lamp flashes seven to nine times and then turns off. If lamp does not operate as specified, refer to Testing And Inspection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Column > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming > Page 7640 Air Bag(s) Arming and Disarming: Service and Repair General Service Precautions CAUTION; When performing service on or around SIR components or SIR wiring, follow the procedures to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > Customer Interest: > 233208A > Aug > 96 > Steering - Crunch/Pop Noise Steering Gear: Customer Interest Steering - Crunch/Pop Noise File In Section: 3 - Steering/Suspension Bulletin No.: 23-32-08A Date: August, 1996 Subject: Steering System Crunch/Pop Noise (Apply Grease/Enlarge Attaching Holes) Models: 1992-96 Buick Roadmaster 1992-93 Cadillac Fleetwood Brougham 1994-96 Cadillac Fleetwood 1992-96 Chevrolet Caprice 1994-96 Chevrolet Impala SS 1992 Oldsmobile Custom Cruiser This bulletin is being revised to add the 1996 model year. Please discard Corporate Bulletin Number 23-32-08 (Section 3 - Steering/Suspension). Condition Some vehicles may exhibit a steering related crunch and/or pop type noise apparent during low speed turning maneuvers. These conditions can be differentiated from one another not only by the type of noise, but also by when they are generated as indicated below. A. Crunch Noise - May occur only when vehicle is in a full right or left hand turning maneuver. B. Pop Noise - May occur anytime vehicle steering wheel is moved off center in either direction. Cause A. Crunch Noise - Movement of lower control arm steering stop on steering knuckle during full turn type maneuvers. B. Pop Noise - Slight movement between steering gear bolt threads and frame rail inboard steering gear attaching holes. Correction Crunch Noise - Apply a thin film (approximately 1 mm thick) of high temperature water resistant grease, P/N 12345996 (1.75 oz. tube), to the contacting surfaces of both the steering stops and steering knuckles. Pop Noise - Follow procedure below and enlarge the frame-rail inboard steering gear attaching holes that show any contact with bolt threads. 1. Disconnect and remove air cleaner snorkle. 2. Disconnect intermediate steering shaft coupling shield and slide rearward. 3. Remove nut securing ABS module bracket to steering gear. 4. Raise vehicle. Notice: Ensure that the vehicle's wheels are pointing straight ahead and the steering wheel is in "LOCK" position. Failure to do so may cause the steering wheel to rotate, causing damage to the coil assembly. 5. Remove left front wheel and tire assembly. 6. Remove flexible coupling bolt and disengage coupling from steering gear. 7. Remove three (3) steering gear to frame rail attaching bolts and position gear away from frame rail. 8. Inspect inboard frame rail steering gear attaching holes for any indication of bolt thread contact. 9. Carefully enlarge those holes that show bolt thread contact utilizing a rat-tail mill file. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > Customer Interest: > 233208A > Aug > 96 > Steering - Crunch/Pop Noise > Page 7649 10. Position steering gear to frame rail and hand start attaching bolts. Torque attaching bolts in sequence # 1, # 2 and # 3 to 95 N.m (70 lb ft) as shown in illustration. 11. Connect flexible coupling to steering gear, install bolt and torque to 31 N.m (23 lb ft). Notice: Ensure that vehicle wheels are pointing straight ahead prior to connecting flexible coupling. 12. Install wheel and tire assembly and torque wheel nuts to 135 N.m (100 lb ft). 13. Lower vehicle. 14. Slide coupling shield forward and secure in position. 15. Install ABS module bracket nut and torque to 60 N.m (44 lb ft). 16. Install and connect air cleaner snorkle. 17. Start vehicle and cycle the steering lock to lock several times. 18. Loosen but do not remove attaching bolts # 1 and # 2, start vehicle and cycle the steering lock to lock several times. 19. Torque attaching bolt # 2 and then # 1 to 95 N.m (70 lb ft). Parts Information Parts are currently available from GMSPO. Warranty Information Labor Operation Labor Time (A) E7001 (A) 0.3 hr Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > Customer Interest: > 233208A > Aug > 96 > Steering - Crunch/Pop Noise > Page 7650 (B) E7002 (B) 0.8 hr Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Steering Gear: > 83-32-10 > Nov > 98 > Tools - Adjuster Locknut Wrench Steering Gear: All Technical Service Bulletins Tools - Adjuster Locknut Wrench File In Section: 3 - Steering/Suspension Bulletin No.: 83-32-10 Date: November, 1998 INFORMATION Subject: Essential Tool J 43435 Adjuster Locknut Wrench Models: 1990-99 Passenger Cars and Trucks with Integral Power Steering A new essential tool, J 43435 Adjuster Locknut Wrench, has been sent to all GM Dealers. This tool should be used on all Integral power steering gears, both past and current models. The following procedure should be used In place of existing Service Manual procedures for Coupling Shield and Locknut Removal and Replacement. The correct adjustment procedure and use of the essential tools are critical to restore the vehicle "On Center" feel (See Figure 1). Important: Coupling shield retainer and locknut assembly replacement procedures require the following special tools: J 42882 Adjuster Nut Wrench J 43435 Adjuster Locknut Wrench Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Steering Gear: > 83-32-10 > Nov > 98 > Tools - Adjuster Locknut Wrench > Page 7656 (See Figure 2) Procedure 1. Place J 42882 over the end of the stub shaft. Place J 43435 over the end. J 43435 is reversible and can be used with both old and new style coupling shield retainers and locknuts. 2. Tighten the coupling shield retainer and locknut assembly after an adjustment or repair has been made to the power steering gear to the specified torque (See Figure 3). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Steering Gear: > 233208A > Aug > 96 > Steering - Crunch/Pop Noise Steering Gear: All Technical Service Bulletins Steering - Crunch/Pop Noise File In Section: 3 - Steering/Suspension Bulletin No.: 23-32-08A Date: August, 1996 Subject: Steering System Crunch/Pop Noise (Apply Grease/Enlarge Attaching Holes) Models: 1992-96 Buick Roadmaster 1992-93 Cadillac Fleetwood Brougham 1994-96 Cadillac Fleetwood 1992-96 Chevrolet Caprice 1994-96 Chevrolet Impala SS 1992 Oldsmobile Custom Cruiser This bulletin is being revised to add the 1996 model year. Please discard Corporate Bulletin Number 23-32-08 (Section 3 - Steering/Suspension). Condition Some vehicles may exhibit a steering related crunch and/or pop type noise apparent during low speed turning maneuvers. These conditions can be differentiated from one another not only by the type of noise, but also by when they are generated as indicated below. A. Crunch Noise - May occur only when vehicle is in a full right or left hand turning maneuver. B. Pop Noise - May occur anytime vehicle steering wheel is moved off center in either direction. Cause A. Crunch Noise - Movement of lower control arm steering stop on steering knuckle during full turn type maneuvers. B. Pop Noise - Slight movement between steering gear bolt threads and frame rail inboard steering gear attaching holes. Correction Crunch Noise - Apply a thin film (approximately 1 mm thick) of high temperature water resistant grease, P/N 12345996 (1.75 oz. tube), to the contacting surfaces of both the steering stops and steering knuckles. Pop Noise - Follow procedure below and enlarge the frame-rail inboard steering gear attaching holes that show any contact with bolt threads. 1. Disconnect and remove air cleaner snorkle. 2. Disconnect intermediate steering shaft coupling shield and slide rearward. 3. Remove nut securing ABS module bracket to steering gear. 4. Raise vehicle. Notice: Ensure that the vehicle's wheels are pointing straight ahead and the steering wheel is in "LOCK" position. Failure to do so may cause the steering wheel to rotate, causing damage to the coil assembly. 5. Remove left front wheel and tire assembly. 6. Remove flexible coupling bolt and disengage coupling from steering gear. 7. Remove three (3) steering gear to frame rail attaching bolts and position gear away from frame rail. 8. Inspect inboard frame rail steering gear attaching holes for any indication of bolt thread contact. 9. Carefully enlarge those holes that show bolt thread contact utilizing a rat-tail mill file. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Steering Gear: > 233208A > Aug > 96 > Steering - Crunch/Pop Noise > Page 7661 10. Position steering gear to frame rail and hand start attaching bolts. Torque attaching bolts in sequence # 1, # 2 and # 3 to 95 N.m (70 lb ft) as shown in illustration. 11. Connect flexible coupling to steering gear, install bolt and torque to 31 N.m (23 lb ft). Notice: Ensure that vehicle wheels are pointing straight ahead prior to connecting flexible coupling. 12. Install wheel and tire assembly and torque wheel nuts to 135 N.m (100 lb ft). 13. Lower vehicle. 14. Slide coupling shield forward and secure in position. 15. Install ABS module bracket nut and torque to 60 N.m (44 lb ft). 16. Install and connect air cleaner snorkle. 17. Start vehicle and cycle the steering lock to lock several times. 18. Loosen but do not remove attaching bolts # 1 and # 2, start vehicle and cycle the steering lock to lock several times. 19. Torque attaching bolt # 2 and then # 1 to 95 N.m (70 lb ft). Parts Information Parts are currently available from GMSPO. Warranty Information Labor Operation Labor Time (A) E7001 (A) 0.3 hr Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Steering Gear: > 233208A > Aug > 96 > Steering - Crunch/Pop Noise > Page 7662 (B) E7002 (B) 0.8 hr Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > All Other Service Bulletins for Steering Gear: > 83-32-10 > Nov > 98 > Tools - Adjuster Locknut Wrench Steering Gear: All Technical Service Bulletins Tools - Adjuster Locknut Wrench File In Section: 3 - Steering/Suspension Bulletin No.: 83-32-10 Date: November, 1998 INFORMATION Subject: Essential Tool J 43435 Adjuster Locknut Wrench Models: 1990-99 Passenger Cars and Trucks with Integral Power Steering A new essential tool, J 43435 Adjuster Locknut Wrench, has been sent to all GM Dealers. This tool should be used on all Integral power steering gears, both past and current models. The following procedure should be used In place of existing Service Manual procedures for Coupling Shield and Locknut Removal and Replacement. The correct adjustment procedure and use of the essential tools are critical to restore the vehicle "On Center" feel (See Figure 1). Important: Coupling shield retainer and locknut assembly replacement procedures require the following special tools: J 42882 Adjuster Nut Wrench J 43435 Adjuster Locknut Wrench Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > All Other Service Bulletins for Steering Gear: > 83-32-10 > Nov > 98 > Tools - Adjuster Locknut Wrench > Page 7668 (See Figure 2) Procedure 1. Place J 42882 over the end of the stub shaft. Place J 43435 over the end. J 43435 is reversible and can be used with both old and new style coupling shield retainers and locknuts. 2. Tighten the coupling shield retainer and locknut assembly after an adjustment or repair has been made to the power steering gear to the specified torque (See Figure 3). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Technical Service Bulletins > Page 7669 Steering Gear: Specifications Component .......................................................................................................................................... ....................................................... Torque/Ft. Lbs. Adjuster Plug Locknut .......................................................................................................................... ............................................................................. 80 Pinion Preload [01] ........................................... .............................................................................................................................................................. 6-10 Rack & Pinion Guide Clamp [01] Screw ...................................................................................... ..................................................................................... 43 Rack Piston Plug ...................................... .............................................................................................................................................................. .......... 111 Steering Gear Adjuster Locknut ........................................................................................ ................................................................................................. 36 [01] Inch lbs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Adjustments > Pitman Shaft Over-Center Preload Steering Gear: Adjustments Pitman Shaft Over-Center Preload Fig. 11 Stub Shaft Alignment Fig. 12 Pitman Shaft Master Spline Alignment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Adjustments > Pitman Shaft Over-Center Preload > Page 7672 Fig. 13 Overcenter Rotational Torque Inspection 1. Rotate stub shaft back and forth to drain fluid. 2. Turn pitman shaft adjuster screw counterclockwise until fully extended, then turn back one full turn, Fig. 11. 3. Rotate stub shaft from stop to stop and count the turns. 4. Starting at either stop, turn the stub shaft back one-half the total number of turns. 5. When the gear is centered, the flat on stub shaft should face upward and be parallel with side cover and master spline on pitman shaft should be inline with adjuster screw, Fig. 12. 6. Rotate stub shaft 45 ° each side of center using a torque wrench with handle in vertical position, Fig. 13, record the highest drag torque measured on or near center. 7. Adjust overcenter drag torque by loosening adjuster locknut and turning the pitman shaft adjuster screw clockwise until correct drag tightness is obtained. On new steering gears (under 400 miles) add 5-11 inch lbs. to previously measured worm bearing preload. Do not exceed total preload of 18 inch lbs. On used steering gears (400 miles or more) add 4-5 inch lbs. to previously measured worm bearing preload. Do not exceed total gear preload of 13 inch lbs. 8. Hold adjuster screw and torque adjuster locknut to 22 ft. lbs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Adjustments > Pitman Shaft Over-Center Preload > Page 7673 Steering Gear: Adjustments Steering Gear Adjustment Adjustment of steering gear in the vehicle is not recommended because of the difficulty encountered in adjusting the worm thrust bearing preload and confirming the effects of the hydraulic fluid in the gear. Since a gear adjustment is made only as a correction and not a periodic adjustment, it is better to take the extra time and make the adjustment correctly the first time. Since a handling stability complaint can be caused by improperly adjusted worm thrust bearings as well as an improper gear overcenter adjustment, it is necessary that the steering gear assembly be removed from vehicle and both thrust bearing and overcenter preload be checked and corrected as necessary. An in-vehicle check of steering gear will not show a thrust bearing adjustment error. Valve assembly and seal drag should be 1-4 inch lbs. Thrust bearing preload should be 3-4 inch lbs. in excess of valve assembly and seal drag. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Service and Repair > Power Steering Gear Steering Gear: Service and Repair Power Steering Gear Fig. 13 Power Steering Gear Mount 1. Disconnect battery ground cable. 2. Disconnect pressure and return hoses from power steering gear. Position hoses in upward direction to prevent fluid drainage. Cap lines and fittings. 3. Disconnect intermediate steering shaft from steering gear stub shaft. 4. Disconnect Pitman arm from steering gear. 5. On models equipped with ABS brake systems, remove ABS modulator bracket attaching nut from steering gear. 6. On all models, remove steering attaching bolts and washers, then remove steering gear, Fig. 13 7. Reverse procedure to install. Tighten attaching bolts to specifications. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Service and Repair > Power Steering Gear > Page 7676 Steering Gear: Service and Repair Saginaw Rotary Valve Type Power Steering Gears Fig. 9 Exploded View Of Saginaw Rotary Valve Power Steering Gear Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Service and Repair > Power Steering Gear > Page 7677 Fig. 10 Service Procedures (Part 1 Of 4) Saginaw Rotary Valve Power Steering Gear Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Service and Repair > Power Steering Gear > Page 7678 Fig. 10 Service Procedures (Part 2 Of 4) Saginaw Rotary Valve Power Steering Gear Component Service Whenever a part which forms a sealing surface for an O-ring is removed, the O-ring seal should also be removed and replaced with a new seal. Whenever one of the Pitman shaft or stub shaft seals are removed, all adjacent seals should be removed and replaced with new seals. Lubricate all new seals with power steering fluid to facilitate assembly. For service procedures on this power steering gear assembly, refer to Figs. 9 and 10. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Service and Repair > Power Steering Gear > Page 7679 Fig. 10 Service Procedures (Part 3 Of 4) Saginaw Rotary Valve Power Steering Gear Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Gear > Component Information > Service and Repair > Power Steering Gear > Page 7680 Fig. 10 Service Procedures (Part 4 Of 4) Saginaw Rotary Valve Power Steering Gear Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Steering > Steering Wheel > Component Information > Service and Repair Steering Wheel: Service and Repair Fig. 14 Steering Wheel With Air Bag Mark position of steering wheel in relation to shaft prior to removal to ensure correct installation. 1. Disconnect battery ground cable. 2. Using a No. 30 Torx driver, loosen air bag inflator module attaching screws until module can be released from steering wheel, Fig. 14. 3. Pull module rearward, then disconnect coil, connector position assurance and horn lead connectors, then remove module. Do not carry module by connectors or wires, when placing live module on bench, place bag and trim cover upward. 4. Remove steering wheel attaching nut. 5. Using suitable steering wheel puller, remove steering wheel and horn contact. 6. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Axle Beam > Component Information > Description and Operation Axle Beam: Description and Operation In these rear axles, the rear axle housing and differential carrier are cast into an integral housing assembly. The drive pinion assembly is mounted in two opposed tapered roller bearings. The pinion bearings are preloaded by a spacer behind the front bearing. The pinion is positioned by a washer between the head of the pinion and the rear bearing. The differential is supported in the carrier by two tapered roller side bearings. These bearings are preloaded by spacers located between the bearings and carrier housing. The differential assembly is positioned for proper ring gear and pinion backlash by varying these spacers. The differential case houses two side gears in mesh with two pinions mounted on a pinion shaft which is held in place by a lockpin. The side gears and pinions are backed by thrust washers. A limited slip rear axle, available on most models, uses disc or cone type clutches which are splined to the side gears to lock the axle shafts to the case or in effect to each other. Therefore, if one drive wheel is on a slippery surface, the other wheel must develop more torque than on a standard type differential before the differential case will allow wheel spin. However, axle shaft torques produced during cornering are sufficient to overcome the clutch action, allowing axles to rotate at different speeds. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Axle Beam > Component Information > Service and Repair > Rear Axle Axle Beam: Service and Repair Rear Axle Construction of the axle assembly is such that service operations may be performed with the housing installed in the vehicle or with the housing removed and installed in a holding fixture.The following procedure is necessary only when the housing requires replacement. 1. Raise and support vehicle, then support rear axle with a suitable jack. 2. On models equipped with anti-lock brake systems, remove rear axle speed sensor as follows: a. Disconnect speed sensor electrical harness. b. Remove speed sensor harness bracket attaching bolt. c. Remove speed sensor to rear axle attaching bolt, then remove speed sensor and bracket assembly and position aside. 3. On all models, disconnect shock absorbers from lower mountings. 4. Remove propeller shaft. 5. Disconnect upper control arms from axle housing attachments. 6. Disconnect brake line from axle housing junction block and parking brake cable. 7. Disconnect lower control arms from axle housing attachments. 8. Lower axle slowly until springs can be moved. Roll axle assembly out from under vehicle. 9. Reverse procedure to install, noting the following: a. Install anti-lock brake system wheel speed sensors by hand. Do not hammer sensors into position as damage may result. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Axle Beam > Component Information > Service and Repair > Rear Axle > Page 7690 Axle Beam: Service and Repair Rear Axle Shaft Fig. 1 Pinion Shaft Lock Bolt & C-lock Removal 1. Raise vehicle and remove wheel and brake drum or rotor. 2. Drain lube from carrier and remove cover. 3. Remove differential pinion shaft lock bolt and remove differential pinion shaft, Fig. 1, 4. Pull flanged end of axle shaft toward center of vehicle and remove C-lock from button end of shaft. 5. Remove axle shaft from housing, being careful not to damage seal. 6. Reverse procedure to install axle shaft. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Technical Service Bulletins > Recalls for Ball Joint: > 96C14A > Apr > 96 > Recall - Lower Control Arm Ball Joint (Supplement) Technical Service Bulletin # 96C14A Date: 960401 Recall - Lower Control Arm Ball Joint (Supplement) CHEVROLET No.: 96-C-14A Date: 04-01-96 Subject: PRODUCT SAFETY CAMPAIGN 96-C-14(a) - LOWER CONTROL ARM BALL JOINT --- Supplement --Model and Year: 1995 -96 CHEVROLET CAPRICE/IMPALA POLICE SEDANS (SEO 9C1), TAXI CAB (SEO 9C6) AND SPECIAL SERVICE WAGON (SEO lA2) AND RETAIL UNITS To: All Chevrolet Dealers This bulletin supplements Product Safety Campaign 96-C-14 issued February, 1996. Specifically, the Vehicles Involved section has been revised to reflect the additional of retail (non-police/taxi) passenger units and the Service Procedure has been revised to reflect a final ball joint nut torque range. Additionally, a revised owner letter is attached. The revised information is printed in bold type. This supplement should be filed with your campaign materials. Vehicles Involved Involved are certain 1995-96 Chevrolet Caprice/Impala Police Sedans, Taxi Cabs, Special Service Wagons and Retail Passenger vehicles (sedans & wagons) built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. SUPPLEMENTAL computer listings for retail units contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign. These listings may contain owner name and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Service Procedure INSPECTION - NUT TORQUE (To Be Performed On Both Sides) 3. Utilizing a clicker type torque wrench set at 60 Nm (44 lb. ft.) and while attempting to tighten lower ball stud nut, determine which of the following conditions exists and proceed as required: A.) Torque Wrench Clicks Prior To Nut Rotation [Nut torqued to more than 60 Nm (44 lb. ft.) as installed] I. Reset torque wrench to between 95 Nm (70 lb. ft.) to 112 Nm (83 lb. ft.) Tighten ball joint nut until wrench clicks. 8. NO GAP: (Ball stud IS NOT seated in knuckle) Replace knuckle and lower ball stud following applicable Service Manual Procedure, Section 3C-3, Front suspension. Check and adjust wheel alignment and toe-in after new knuckle and lower ball stud is installed. Proceed to Step 10. OR GAP: (Ball stud is seated in knuckle) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Technical Service Bulletins > Recalls for Ball Joint: > 96C14A > Apr > 96 > Recall - Lower Control Arm Ball Joint (Supplement) > Page 7699 Tighten nut and torque to between 95 Nm (70 lb. ft.) to 112 Nm (83 lb. ft.), then tighten nut enough to align slot in nut with hole in ball stud and install new cotter pin. Nut rotation to align cotter pin hole is not to exceed one flat (60 degrees). Owner Letter Dear Chevrolet Caprice/Impala Owner: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that a defect which relates to motor vehicle safety exists in some 1995-96 Chevrolet Caprice/Impala vehicles. The lower control arm ball joint attachment nut may be loose. This condition can cause the lower control arm ball joint to loosen, fatigue and separate from the front suspension knuckle. If separation were to occur with the vehicle in motion, loss of vehicle control may occur which could result in a vehicle crash without prior warning. WHAT WE WILL DO To correct this condition, all involved vehicles will have both front lower control arm ball joint attachment nuts inspected for proper torque. If the ball joint has loosened from the knuckle, both the ball joint and knuckle will be replaced. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date and so they may inspect your vehicle and if necessary order the necessary parts for the repair. Instructions for making this correction have been sent to your dealer and parts are available. The labor time necessary to perform this inspection/service correction is approximately 20 minutes to 3-1/2 hours. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the Administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your safety and continue satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Ball Joint: > 96C14A > Apr > 96 > Recall - Lower Control Arm Ball Joint (Supplement) Technical Service Bulletin # 96C14A Date: 960401 Recall - Lower Control Arm Ball Joint (Supplement) CHEVROLET No.: 96-C-14A Date: 04-01-96 Subject: PRODUCT SAFETY CAMPAIGN 96-C-14(a) - LOWER CONTROL ARM BALL JOINT --- Supplement --Model and Year: 1995 -96 CHEVROLET CAPRICE/IMPALA POLICE SEDANS (SEO 9C1), TAXI CAB (SEO 9C6) AND SPECIAL SERVICE WAGON (SEO lA2) AND RETAIL UNITS To: All Chevrolet Dealers This bulletin supplements Product Safety Campaign 96-C-14 issued February, 1996. Specifically, the Vehicles Involved section has been revised to reflect the additional of retail (non-police/taxi) passenger units and the Service Procedure has been revised to reflect a final ball joint nut torque range. Additionally, a revised owner letter is attached. The revised information is printed in bold type. This supplement should be filed with your campaign materials. Vehicles Involved Involved are certain 1995-96 Chevrolet Caprice/Impala Police Sedans, Taxi Cabs, Special Service Wagons and Retail Passenger vehicles (sedans & wagons) built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. SUPPLEMENTAL computer listings for retail units contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign. These listings may contain owner name and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Service Procedure INSPECTION - NUT TORQUE (To Be Performed On Both Sides) 3. Utilizing a clicker type torque wrench set at 60 Nm (44 lb. ft.) and while attempting to tighten lower ball stud nut, determine which of the following conditions exists and proceed as required: A.) Torque Wrench Clicks Prior To Nut Rotation [Nut torqued to more than 60 Nm (44 lb. ft.) as installed] I. Reset torque wrench to between 95 Nm (70 lb. ft.) to 112 Nm (83 lb. ft.) Tighten ball joint nut until wrench clicks. 8. NO GAP: (Ball stud IS NOT seated in knuckle) Replace knuckle and lower ball stud following applicable Service Manual Procedure, Section 3C-3, Front suspension. Check and adjust wheel alignment and toe-in after new knuckle and lower ball stud is installed. Proceed to Step 10. OR GAP: (Ball stud is seated in knuckle) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Ball Joint: > 96C14A > Apr > 96 > Recall - Lower Control Arm Ball Joint (Supplement) > Page 7705 Tighten nut and torque to between 95 Nm (70 lb. ft.) to 112 Nm (83 lb. ft.), then tighten nut enough to align slot in nut with hole in ball stud and install new cotter pin. Nut rotation to align cotter pin hole is not to exceed one flat (60 degrees). Owner Letter Dear Chevrolet Caprice/Impala Owner: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that a defect which relates to motor vehicle safety exists in some 1995-96 Chevrolet Caprice/Impala vehicles. The lower control arm ball joint attachment nut may be loose. This condition can cause the lower control arm ball joint to loosen, fatigue and separate from the front suspension knuckle. If separation were to occur with the vehicle in motion, loss of vehicle control may occur which could result in a vehicle crash without prior warning. WHAT WE WILL DO To correct this condition, all involved vehicles will have both front lower control arm ball joint attachment nuts inspected for proper torque. If the ball joint has loosened from the knuckle, both the ball joint and knuckle will be replaced. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date and so they may inspect your vehicle and if necessary order the necessary parts for the repair. Instructions for making this correction have been sent to your dealer and parts are available. The labor time necessary to perform this inspection/service correction is approximately 20 minutes to 3-1/2 hours. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the Administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your safety and continue satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Technical Service Bulletins > Page 7706 Ball Joint: Testing and Inspection Fig. 4 Upper Ball Joint Wear Inspection 1. Raise and support vehicle. Position jack stands under lower control arm as close to lower ball joint as possible. 2. Position a suitable dial indicator against wheel rim, Fig. 4 3. Grasp wheel at top and bottom, then pull top of wheel outward, while pushing inward on bottom of wheel. Note dial indicator reading. 4. Pull bottom of wheel outward, while pushing inward on top of wheel. Note dial indicator reading. 5. Deflection reading on dial indicator should not exceed .125 inch. 6. If reading exceeds .125 inch, replace upper ball joint. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Service and Repair > Upper Ball Joint Replacement Ball Joint: Service and Repair Upper Ball Joint Replacement Fig. 6 Upper Ball Joint Separation From Steering Knuckle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Service and Repair > Upper Ball Joint Replacement > Page 7709 Fig. 7 Upper Ball Joint Installation 1. Raise vehicle and support with stands at outer ends of lower control arms. 2. Remove wheel and tire. 3. Remove cotter pin and retaining nut, then separate ball joint stud from knuckle using a suitable tool, Fig. 6. 4. Support upper control arm in a raised position. 5. Remove heads of rivets securing joint to arm, then drive out rivets to remove joint. 6. Position replacement joint on top of control arm, insert retaining bolts supplied with joint from under arm, install nuts and tighten to specifications, Fig. 7. 7. Remove upper control arm support, assemble ball joint to steering knuckle, install washer, if equipped, and retaining nut. 8. Tighten retaining nut to specifications. 9. Tighten retaining nut up to an additional 1/16 turn, if necessary, to align hole in ball stud with nut, then install cotter pin. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Service and Repair > Upper Ball Joint Replacement > Page 7710 Ball Joint: Service and Repair Lower Ball Joint Replacement Fig. 8 Lower Ball Joint Separation From Steering Knuckle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Service and Repair > Upper Ball Joint Replacement > Page 7711 Fig. 9 Lower Ball Joint Removal From Lower Control Arm Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Ball Joint > Component Information > Service and Repair > Upper Ball Joint Replacement > Page 7712 Fig. 10 Lower Ball Joint Installation Into Lower Control Arm 1. Raise vehicle and support at frame, and remove wheel and tire. 2. Position a suitable jack under lower control arm spring seat, and raise jack to compress coil spring. Jack must remain in place during ball joint replacement to hold spring and lower control arm in position. 3. Remove cotter pin and nut securing ball joint stud to steering knuckle, then disconnect joint from knuckle using a suitable tool, Fig. 8. 4. Lift knuckle assembly from ball stud, guiding control arm out of splash shield, then support knuckle aside to allow clearance for joint removal. 5. Remove grease fitting, then press ball joint assembly out of lower control arm using a suitable tool, Fig. 9. 6. Press replacement joint into arm using suitable tools, Fig. 10. Fit spindle over ball stud, install washer, if equipped, and retaining nut. 7. Tighten retaining nut to specifications. 8. Tighten nut an additional 1/16 turn, if necessary, to align hole in ball stud with nut, then install cotter pin. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Control Arm > Control Arm Bushing > Component Information > Service and Repair > Differential Carrier Bushings (Upper Control Arm Rear Bushings) Control Arm Bushing: Service and Repair Differential Carrier Bushings (Upper Control Arm Rear Bushings) Fig. 5 Upper Control Arm Rear Bushing (Differential Carrier Bushing) Removal Fig. 6 Upper Control Arm Rear Bushing (Differential Carrier Bushing) Installation The upper control arm rear bushing, which is pressed into the differential carrier, can be replaced using the following procedure: 1. Raise vehicle and support at frame pads, and support nose of axle housing to prevent assembly from twisting. 2. Lower rear axle to obtain clearance, disconnect upper control arm from axle and position aside. 3. Install suitable bushing removal tool as shown in Fig. 5. tighten puller screw and press bushing out of housing. 4. To install replacement bushing, reverse position of removal tool and pull bushing into position by tightening screw, Fig. 6. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Control Arm > Control Arm Bushing > Component Information > Service and Repair > Differential Carrier Bushings (Upper Control Arm Rear Bushings) > Page 7718 Control Arm Bushing: Service and Repair Control Arm Bushings Fig. 7 Control Arm Bushing Removal Fig. 8 Control Arm Bushing Installation 1. Raise and support vehicle and remove control arm. 2. Press bushings out of control arm using suitable tools as shown in Fig. 7 3. Reverse procedure to install, ensuring bushing is properly seated in control arm, Fig. 8. If replacement bushing fits loosely in control arm, or if mounting areas are damaged or deformed, control arm must be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Cross-Member > Component Information > Locations Cross-Member: Locations Center Of Rear Crossmember Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Cross-Member > Component Information > Locations > Page 7722 Antilock Brake System Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Front Steering Knuckle > Component Information > Technical Service Bulletins > Steering Knuckle Nuts - Revised Torque Specification Front Steering Knuckle: Technical Service Bulletins Steering Knuckle Nuts - Revised Torque Specification FILE IN SECTION: 3 - Steering/Suspension BULLETIN NO.: 53-33-02A DATE: June, 1995 SUBJECT: Section 3C - Revised Torque Specification for Steering Knuckle Nuts (Upper and Lower) MODELS: 1993-95 Buick Roadmaster 1993-95 Cadillac Fleetwood 1993-95 Chevrolet Caprice 1994-95 Chevrolet Impala SS The torque specification for upper and lower steering knuckle nuts should be as follows: Tighten ^ Steering knuckle nut (upper) (1) to 83 Nm (61 lb.ft.), additional tightening may be required to insert cotter pin (3). Do not exceed 60° additional tightening. ^ Steering knuckle nut (lower) (2) to 112 Nm (63 lb.ft.), additional tightening may be required to insert cotter pin (3). Do not exceed 60° additional tightening. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Relays and Modules - Suspension > Compressor/Pump Relay, Suspension Control > Component Information > Description and Operation Compressor/Pump Relay: Description and Operation DESCRIPTION The compressor relay is controlled by the height sensor and completes the 12-volt circuit to the compressor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations Center Of Rear Crossmember Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7735 Ride Height Sensor: Description and Operation DESCRIPTION The height sensor controls two circuits, compressor relay coil ground circuit and exhaust solenoid coil ground circuit. To prevent energizing the compressor relay and exhaust solenoid circuits during normal ride motions, the sensor circuit provides a predetermined delay before the ground circuit is completed. The sensor electronically limits compressor run time and exhaust solenoid energized time. This limit function is necessary to prevent continuous compressor operation in case of a system leak or continuous exhaust solenoid operation. This timer is reset whenever the ignition is turned Off and On, or height sensor exhaust or compressor signal changes. The height sensor is mounted to the body frame in the rear of the vehicle. The sensor actuator arm is attached to the control arm by a short link Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7736 Ride Height Sensor: Testing and Inspection CAUTION: When diagnostic procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Turn ignition Off, then On. This will reset height sensor timer circuits. 2. Raise vehicle on hoist. Ensure rear wheels or axle housing are supported and that vehicle is at proper trim height. 3. Disconnect link from height sensor arm, then ensure sensor wiring and harness ground are connected properly. 4. Move sensor arm upward. There should be a delay of 8-15 seconds before compressor turns on and shocks start to inflate. As soon as shocks start to fill, stop compressor by moving sensor arm down. 5. Move sensor arm down below position where compressor stopped. There should be a delay of 8-15 seconds before shocks start to deflate and vehicle lowers. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7737 Ride Height Sensor: Adjustments ADJUSTMENTS The link should be properly attached to the sensor arm and track bar, when making this adjustment. 1. Loosen lock bolt securing metal arm to height sensor plastic arm. 2. To raise vehicle trim height, move plastic arm upward and tighten lock bolt. 3. To lower vehicle trim height, loosen lock bolt securing metal arm to height sensor plastic arm, then move plastic arm down. 4. If adjustment cannot be made, check for correct sensor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Sensors and Switches - Suspension > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7738 Ride Height Sensor: Service and Repair WARNING: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Disconnect battery ground cable. 2. Raise and support vehicle. 3. Disconnect harness from sensor electrical connector by squeezing oval sides of the connector lock to release locking tabs. 4. Remove link from height sensor arm, then remove sensor mounting screws or nuts and the sensor. 5. Remove sensor mounting bracket to underbody attaching screws and remove bracket. 6. Reverse procedure to install, noting the following: a. When connecting harness to sensor electrical connector, push connector into sensor plug until sloped shoulder on rear edge of boss is visible in plug slot. Push oval connector lock onto plug until its two locking tabs snap over shoulder of sensor plug. b. Perform height sensor operational check and adjustment procedure as described under Testing and Inspection. See: Testing and Inspection Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Stabilizer Shaft <--> [Stabilizer Bar, Sway Control] > Component Information > Service and Repair Stabilizer Shaft: Service and Repair 1. Support vehicle at rear axle. 2. Remove bolts securing stabilizer bar to lower control arms. 3. Reverse procedure to install. Use spacer shims, if needed, placed equally on each side of stabilizer bar. Tighten attaching bolts with vehicle at curb height. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Air Dryer, Suspension Control > Component Information > Description and Operation Air Dryer: Description and Operation DESCRIPTION The air dryer, attached to the compressor outlet, performs two system functions. The dryer contains a dry chemical that absorbs moisture from the air before it is delivered to the shocks. Moisture is removed from the chemical and returned to the air when system is being exhausted. The air dryer also contains a valving arrangement that maintains a minimum air pressure of 7-14 psi in the shocks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Air Dryer, Suspension Control > Component Information > Description and Operation > Page 7746 Air Dryer: Testing and Inspection CAUTION; When diagnostic procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. Fig. 21 Compressor/Dryer Trouble Chart 1. Disconnect wiring from compressor motor and exhaust solenoid terminals. 2. Disconnect existing pressure line from dryer and attach pressure gauge tool No. J 22124-A or equivalent to dryer fitting. 3. Connect an ammeter to 12 volt source and to compressor. 4. Operate compressor and note the following: a. Current draw should not exceed 14 amps. b. When gauge reads at least 100 psi, turn compressor Off by disconnecting power supply and observe if pressure leaks down. Compressor should not leak below 90 psi. If compressor is permitted to run until it reaches maximum output pressure of 180 psi, the solenoid exhaust valve will act as a relief valve. The resulting leak down when compressor is shutoff will indicate a false leak. c. Refer to chart shown in Fig. 21 if compressor fails to meet specification. d. If performance is satisfactory, install compressor and connect wiring and air lines. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Air Dryer, Suspension Control > Component Information > Description and Operation > Page 7747 Air Dryer: Service and Repair CAUTION: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. Fig. 23 Air Dryer Assembly 1. Remove compressor as described in Shield, Compressor & Bracket. See: Compressor/Pump/Service and Repair/Shield, Compressor & Bracket 2. Rotate dryer retainer spring 90° and pull dryer and O-ring out of compressor head assembly, Fig. 23. 3. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Locations Front Frame Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Locations > Page 7751 Compressor/Pump: Description and Operation DESCRIPTION This assembly is a single-piston air pump powered by a 12-volt DC permanent magnet motor. The compressor head casting contains intake and exhaust valves plus a solenoid-operated exhaust valve which releases air from the system when energized. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Locations > Page 7752 Compressor/Pump: Testing and Inspection CAUTION: When diagnostic procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. Fig. 21 Compressor/Dryer Trouble Chart 1. Disconnect wiring from compressor motor and exhaust solenoid terminals. 2. Disconnect existing pressure line from dryer and attach pressure gauge tool No. J 22124-A or equivalent to dryer fitting. 3. Connect an ammeter to 12 volt source and to compressor. 4. Operate compressor and note the following: a. Current draw should not exceed 14 amps. b. When gauge reads at least 100 psi, turn compressor Off by disconnecting power supply and observe if pressure leaks down. Compressor should not leak below 90 psi. If compressor is permitted to run until it reaches maximum output pressure of 180 psi, the solenoid exhaust valve will act as a relief valve. The resulting leak down when compressor is shutoff will indicate a false leak. c. Refer to chart shown in Fig. 21 if compressor fails to meet specification. d. If performance is satisfactory, install compressor and connect wiring and air lines. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Service and Repair > Compressor Head Assembly Compressor/Pump: Service and Repair Compressor Head Assembly Fig. 24 Compressor Head Assembly 1. Remove air dryer assembly as described in AIR DRYER. See: Air Dryer/Service and Repair 2. Remove three compressor head mounting bolts and head assembly, Fig. 24. 3. Reverse procedure to install, using a new O-ring and torquing head mounting bolts to 36 inch lbs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Service and Repair > Compressor Head Assembly > Page 7755 Compressor/Pump: Service and Repair Shield, Compressor & Bracket CAUTION: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Disconnect battery ground cable. 2. Raise and support vehicle. 3. Remove compressor shield, if equipped, then deflate system. 4. Disconnect high pressure line at air dryer by revolving spring clip 90° while holding connector end and removing tube assembly. 5. Disconnect electrical connector from compressor pigtail harness. 6. Remove three compressor mounting screws, then the compressor. 7. Remove three compressor mounting bracket screws, then the bracket. 8. If replacing compressor assembly, remove dryer and dryer bracket. 9. Reverse procedure to install. After connecting battery ground cable, cycle ignition switch, then test system operation, looking for air leaks at dryer. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Service and Repair > Compressor Head Assembly > Page 7756 Compressor/Pump: Service and Repair Solenoid Valve Assembly CAUTION: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. If solenoid valve assembly requires replacement, it should be replaced with compressor head assembly. Refer to COMPRESSOR HEAD ASSEMBLY. See: Compressor Head Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Service and Repair > Compressor Head Assembly > Page 7757 Compressor/Pump: Service and Repair Air Compressor Service CAUTION: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. Fig. 25 Air Compressor, Disassembled Disassembly 1. Remove the seven compressor cover screws, then the compressor cover and gasket, Fig. 25. 2. Remove head and solenoid assembly. 3. Remove two filters, exhaust valve, spring and air dryer O-ring from head assembly. 4. Remove solenoid from head by lifting slightly and sliding to the dryer outlet side. 5. Remove O-ring from solenoid assembly. 6. Remove head gasket from cylinder assembly. 7. Remove four mounting bracket screws, then the bracket and gasket. Note position of ground wire for installation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump, Suspension Control > Component Information > Service and Repair > Compressor Head Assembly > Page 7758 Fig. 26 Air Compressor Head Tightening Sequence Assembly 1. Install gasket and mounting bracket, then the ground wire and screws. 2. Install head gasket on cylinder assembly. 3. Install O-ring on solenoid assembly, then the solenoid in the head with valve opposite air dryer outlet. 4. Install two filters, exhaust valve and spring on head assembly. 5. Install gasket and cover on head assembly, then four short cover screws. 6. Install head and cover assembly to cylinder assembly using three long screws. Torque all seven screws in sequence, Fig. 26, to 36 inch lbs. 7. Install air dryer O-ring on compressor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Compressor/Pump Relay, Suspension Control > Component Information > Description and Operation Compressor/Pump Relay: Description and Operation DESCRIPTION The compressor relay is controlled by the height sensor and completes the 12-volt circuit to the compressor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Level Control Solenoid Valve > Component Information > Description and Operation Level Control Solenoid Valve: Description and Operation DESCRIPTION The exhaust solenoid is located in the compressor head assembly and provides two functions. The solenoid exhausts air from the system when energized by the height sensor. It also acts as a pressure relief valve to limit maximum pressure output of the compressor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Ride Height Sensor, Suspension Control > Component Information > Locations Center Of Rear Crossmember Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7768 Ride Height Sensor: Description and Operation DESCRIPTION The height sensor controls two circuits, compressor relay coil ground circuit and exhaust solenoid coil ground circuit. To prevent energizing the compressor relay and exhaust solenoid circuits during normal ride motions, the sensor circuit provides a predetermined delay before the ground circuit is completed. The sensor electronically limits compressor run time and exhaust solenoid energized time. This limit function is necessary to prevent continuous compressor operation in case of a system leak or continuous exhaust solenoid operation. This timer is reset whenever the ignition is turned Off and On, or height sensor exhaust or compressor signal changes. The height sensor is mounted to the body frame in the rear of the vehicle. The sensor actuator arm is attached to the control arm by a short link Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7769 Ride Height Sensor: Testing and Inspection CAUTION: When diagnostic procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Turn ignition Off, then On. This will reset height sensor timer circuits. 2. Raise vehicle on hoist. Ensure rear wheels or axle housing are supported and that vehicle is at proper trim height. 3. Disconnect link from height sensor arm, then ensure sensor wiring and harness ground are connected properly. 4. Move sensor arm upward. There should be a delay of 8-15 seconds before compressor turns on and shocks start to inflate. As soon as shocks start to fill, stop compressor by moving sensor arm down. 5. Move sensor arm down below position where compressor stopped. There should be a delay of 8-15 seconds before shocks start to deflate and vehicle lowers. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7770 Ride Height Sensor: Adjustments ADJUSTMENTS The link should be properly attached to the sensor arm and track bar, when making this adjustment. 1. Loosen lock bolt securing metal arm to height sensor plastic arm. 2. To raise vehicle trim height, move plastic arm upward and tighten lock bolt. 3. To lower vehicle trim height, loosen lock bolt securing metal arm to height sensor plastic arm, then move plastic arm down. 4. If adjustment cannot be made, check for correct sensor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Control ( Automatic - Electronic ) > Ride Height Sensor, Suspension Control > Component Information > Locations > Page 7771 Ride Height Sensor: Service and Repair WARNING: When repair or adjustment procedures require that vehicle be raised on a hoist, it is important that the rear axle assembly remains in the normal trim height position at all times. When a frame contact hoist is used, two additional jack stands should be used to support the rear axle or control arms in the normal trim height position. 1. Disconnect battery ground cable. 2. Raise and support vehicle. 3. Disconnect harness from sensor electrical connector by squeezing oval sides of the connector lock to release locking tabs. 4. Remove link from height sensor arm, then remove sensor mounting screws or nuts and the sensor. 5. Remove sensor mounting bracket to underbody attaching screws and remove bracket. 6. Reverse procedure to install, noting the following: a. When connecting harness to sensor electrical connector, push connector into sensor plug until sloped shoulder on rear edge of boss is visible in plug slot. Push oval connector lock onto plug until its two locking tabs snap over shoulder of sensor plug. b. Perform height sensor operational check and adjustment procedure as described under Testing and Inspection. See: Testing and Inspection Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Spring ( Coil / Leaf ) > Component Information > Service and Repair > Front Coil Spring Suspension Spring ( Coil / Leaf ): Service and Repair Front Coil Spring Fig. 11 Coil Spring Position 1. Raise and support front of vehicle, then remove wheel and tire assembly. Support vehicle by frame so control arms hang free. 2. On models equipped with anti-lock brake systems, remove right and left wheel speed sensors as follows: a. Under vehicle hood, disconnect speed sensor electrical harness. b. Raise and support vehicle, then remove speed sensor harness bracket attaching bolt. c. Remove speed sensor to steering knuckle attaching bolt, then remove speed sensor and bracket assembly and position aside. d. Reverse procedure to install. Wheel speed sensors are to installed by hand. Do not hammer sensors into position, as damage may result. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Spring ( Coil / Leaf ) > Component Information > Service and Repair > Front Coil Spring > Page 7776 3. On all models, remove stabilizer to lower control arm attachment. 4. Disconnect tie rod end from steering knuckle. 5. Install a suitable coil spring compressor, then compress coil spring. 6. Remove lower control arm to frame bolts, then pivot lower control arm rearward. 7. Carefully loosen coil spring compressor and remove coil spring from vehicle. 8. Reverse procedure to install. Position coil spring as shown in Fig. 11. Install front pivot bolt first. To ensure adequate suspension clearance, install front pivot bolt from front, with nut toward rear of vehicle. Rear bolt can be installed from either direction. 9. Tighten pivot bolts to specifications. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Spring ( Coil / Leaf ) > Component Information > Service and Repair > Front Coil Spring > Page 7777 Suspension Spring ( Coil / Leaf ): Service and Repair Rear Coil Spring Fig. 3 Coil Spring Installation If more than one coil spring is being replaced, remove and install one spring at a time to prevent axle assembly from slipping or twisting out of position. 1. Support vehicle at frame and rear axle. 2. On models equipped with anti-lock brake systems, remove rear axle speed sensor as follows: a. Disconnect speed sensor electrical harness. b. Remove speed sensor harness bracket attaching bolt. c. Remove speed sensor to rear axle attaching bolt, then remove speed sensor and bracket assembly and position aside. 3. On all models, disconnect shock absorbers at lower mountings. 4. Disconnect upper control arms from axle housing. 5. Disconnect stabilizer bar from either right or lefthand side of control arm, if equipped. 6. On models equipped with electronic suspension, disconnect height sensor arm link. 7. On all models, remove brake hose support bolt and support without disconnecting brake lines. 8. Lower axle until spring can be removed, then remove spring and insulator. 9. Reverse procedure to install, noting the following: a. Springs must be installed with an insulator between upper seat and spring and positioned properly, Fig. 3 b. Install anti-lock brake wheel speed sensors by hand. Do not hammer sensors into position, as damage may result. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Technical Service Bulletins > Suspension - Shock Absorber/Strut Leakage Information Suspension Strut / Shock Absorber: Technical Service Bulletins Suspension - Shock Absorber/Strut Leakage Information INFORMATION Bulletin No.: 05-03-08-002C Date: October 16, 2009 Subject: Information on Replacement of Shock Absorbers and Struts Due to Fluid Leaks Models: 2010 and Prior GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2010 model year and Inspection Procedures. Please discard Corporate Bulletin Number 05-03-08-002B (Section 03 - Suspension). This bulletin is intended to help identify the severity of shock absorber and strut fluid seepage. Improper diagnosis may lead to components being replaced that are within the manufacturer's specification. Shock absorbers and strut assemblies are fluid-filled components and will normally exhibit some seepage. Seepage is defined as oil film or dust accumulation on the exterior of the shock housing. Shock absorbers and struts are not to be replaced under warranty for seepage. Use the following information to determine if the condition is normal acceptable seepage or a defective component. Important Electronically controlled shock absorbers (MR) may have a tendency to attract dust to this oil film. Often this film and dust can be wiped off and will not return until similar mileage is accumulated again. Inspection Procedure Note The shock absorber or strut assembly DOES NOT have to be removed from the vehicle to perform the following inspection procedure. Use the following descriptions and graphics to determine the serviceability of the component. Shock Absorbers Do Not Replace shock absorbers displaying condition 1 or 2 levels of seepage. 1. Oil or fluid residue only on the bottom or top of the shock absorber and not originating from the shaft seal (the upper part of the lower shock tube). 2. Light film/residue on approximately 1/3 (a) or less of the lower shock tube (A) and originating from the shaft seal. Replace shock absorbers displaying conditions 3 and 4 levels of leaks. 3. Oil drip or trail down the lower shock tube and originating from the shaft seal. 4. An extreme wet film of oil covering more than 1/3 (b) of the lower shock tube and originating from the shaft seal. Coil-over Shock Absorber Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Technical Service Bulletins > Suspension - Shock Absorber/Strut Leakage Information > Page 7782 Do Not Replace coil-over shock absorbers displaying condition 1 or 2 levels of seepage. 1. Oil or fluid residue only on the bottom of the lower shock absorber tube or the coil-over shock absorber components and not originating from the shaft seal (located at the top of the coil-over shock tube). 2. Light film/residue on the shock absorber tube, but not on the spring seat and originating from the shaft seal. Replace coil-over shock absorbers displaying conditions 3 and 4 levels of leaks. 3. Oil drip or trail down the lower shock tube and originating from the shaft seal. 4. An extreme, wet film of oil covering the shock absorber tube and pooling in the spring seat and originating from the shaft seal. Struts Do Not Replace Struts displaying condition 1 or 2 levels of seepage. 1. Oil or fluid residue only on the bottom of the strut tube or on other strut components and not originating from the shaft seal. 2. Light film/residue on the strut tube, but not on the spring seat and originating from the shaft seal. Replace Struts displaying conditions 3 and 4 levels of leaks. 3. Oil drip or trail down the strut tube and originating from the shaft seal (located at the top of the strut tube). 4. Extreme wet film of oil covering the strut tube and pooling in the spring seat and originating from the shaft seal. Correction Use the information published in SI for diagnosis and repair. Use the applicable published labor operation. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Technical Service Bulletins > Suspension - Shock Absorber/Strut Leakage Information > Page 7783 Suspension Strut / Shock Absorber: Technical Service Bulletins Suspension - Shock Absorber/Strut Replacement Guidlines File In Section: Warranty Administration Bulletin No.: 72-05-12 Date: January, 1998 WARRANTY ADMINISTRATION Subject: Replacement of Shock Absorbers and Struts Labor Operations E3800, E3801, E3807, E5800, E5801, E5807, E3850, E3851, E3857, E5750, E5751, and E5757 Models: All Past, Present, and Future Passenger Cars & Trucks The purpose of this bulletin is to provide retail and wholesale service personnel with enhanced service policies for the above listed subject labor operations. Service Management should make certain that all dealership personnel responsible for replacement of suspension components are familiar with GM Service Manual procedures. Effective with repair orders dated on or after January 15, 1998 the following must also be followed: - Shock absorber/strut assemblies are fluid filled components and will normally exhibit seepage. Seepage is defined as oil film or dust accumulation on the exterior of the shock housing. Shock absorber/strut assemblies are not to be replaced under warranty or seepage. - Defective shock absorber/strut assemblies will have a visible oil path or drip coming from the component. A visible oil path or drip coming from the shock absorber/strut assembly should be replaced as a defective component. - Only defective shock absorber/strut assemblies should be replaced. DO NOT replace pairs unless both are defective, unless otherwise instructed in the Service Manual and/or Service Bulletin. - Service Management approval is required on the repair order for replacement of struts or shocks in pairs. This approval includes noting the reason for replacement. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Technical Service Bulletins > Page 7784 Suspension Strut / Shock Absorber: Description and Operation DESCRIPTION The shocks are constructed with a plastic sleeve attached to the dust tube and reservoir. This sleeve forms a flexible chamber which will extend the shock when air pressure is increased. In order to maintain proper operation and reliability, a minimum pressure of 7-14 psi must be maintained in the system at all times. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Service and Repair > Front Suspension Shock Absorber Suspension Strut / Shock Absorber: Service and Repair Front Suspension Shock Absorber Front Shock Absorber Attachments Removing Shock Absorber Upper Nut SPECIAL TOOL REQUIRED (or equivalent) ^ J-25591, Shock absorber nut wrench. REMOVE OR DISCONNECT 1. Raise and suitably support vehicle. 2. Hold the shock absorber upper stem using J-25591 to keep it from turning. 3. Nut, retainer and insulator. 4. Lower shock bolts/screws and pull the shock absorber out from the bottom. 5. Inspect lower control arm nuts and replace if necessary. INSTALL OR CONNECT 1. With the retainer and insulator in place over the upper stem, install the shock absorber (fully extended) up through the lower control arm and spring so that the upper stem passes through the mounting hole in the frame. 2. Insulator, retainer and nut over the shock absorber upper stem. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Service and Repair > Front Suspension Shock Absorber > Page 7787 3. Using J-25591, hold the upper stem to keep it from turning and tighten the nut to 11 Nm (97 lb in). 4. Lower shock bolts/screws attaching the shock absorber lower pivot to the control arm and tighten to 27 Nm (20 ft lbs). 5. Lower vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Service and Repair > Front Suspension Shock Absorber > Page 7788 Suspension Strut / Shock Absorber: Service and Repair Rear Suspension (Figure 1) Rear Shock Absorber REMOVE OR DISCONNECT 1. Raise and suitably support vehicle. 2. Support rear axle. 3. Air line from air adjustable shock absorber, if equipped, by turning spring clip 90° and pulling gently on air line housing. 4. Nuts and bolts/screws from shock absorber at frame. CAUTION: When removing the lower attaching nut, the stud must not turn. A hex is located on the stud between the bracket and the shock absorber so that a wrench can be used to keep the stud from turning. Failure to hold the stud may cause damage to the mechanical bond between the shock absorber and the stud. 5. Nut and washer from shock absorber. 6. Shock absorber. 7. Shield from shock absorber, if equipped. INSTALL OR CONNECT 1. Shield to shock absorber, if equipped. Position so that "V" notch near clamp is 180° from air tube fitting and rim of shield is seat against rubber rim of shock absorber boot. 2. Shock absorber. 3. Bolts/screws and nuts loosely at frame. CAUTION: When tightening lower attaching nut, the stud must not turn. A hex is located on the stud between the bracket and the shock absorber so a wrench can be used to keep the stud from turning. Failure to hold the stud may cause damage to the mechanical bond between the shock absorber and the stud. 4. Washer and nut at rear axle housing and tighten nut to 85 Nm (63 lb ft). 5. Air line to air adjustable shock absorber, if equipped. 6. Remove support from rear axle. 7. Lower vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Service and Repair > Front Suspension Shock Absorber > Page 7789 Suspension Strut / Shock Absorber: Service and Repair Strut Air Bladder Fig. 82 Upper Strut Mount Removal. Fig. 83 Outer Clamp Removal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Service and Repair > Front Suspension Shock Absorber > Page 7790 Fig. 84 O-ring Replacement. Fig. 85 Inner Clamp Removal. REMOVAL 1. Remove strut from vehicle. 2. Scribe alignment marks between upper mount and outer tube. 3. Clamp strut in a suitable vise using wooden blocks. 4. Remove upper mount from strut, Fig. 82. 6. Cut and remove outer clamp with a hacksaw, Fig. 83. 6. Cut air bladder from outer tube and slide the inner tube upward. 7. Remove O-ring from inside top of outer tube, Fig. 84. 8. Cut and remove inner clamp with a hacksaw, Fig. 85. 9. Remove air bladder from inner tube. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Service and Repair > Front Suspension Shock Absorber > Page 7791 Fig. 86 Air Bladder Replacement. Fig. 87 Inner Clamp & Air Bladder Positioning. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Suspension Strut / Shock Absorber > Component Information > Service and Repair > Front Suspension Shock Absorber > Page 7792 Fig. 88 Air Fitting Positioning. INSTALLATION 1. Lubricate new O-ring and O-ring groove with silicone lubricant. Install O-ring in groove, Fig. 84. 2. Apply silicone lubricant to inside top of entire outside of new air bladder, Fig. 86. 3. Fold bottom of air bladder before installation on inner tube. Place air bladder over inner tube, continuing to fold bladder from the bottom up. Position top of air bladder as shown in Fig. 87. CAUTION: Do not use tools to fold air bladder as damage may occur, causing air leakage. 4. Place inner clamp in position as shown in Fig. 87. Tighten clamp with sealing ring compressor tool No. J-34649, or equivalent. 5. Fold bottom of air bladder upward and fold top of 4 inch section downward. 6. Apply silicone lubricant to polished diameter of inner shaft tube. 7. Place outer tube over air bladder and push downward against folded portion of bladder. Outer tube must be completely seated over shaft. 8. Install upper mount onto strut, aligning marks made during disassembly, and torque nut to 74 ft. lbs. Upper mount and tube air fitting must be properly positioned with the bottom strut mount, Fig. 88. 9. Apply silicone lubricant to outer tube. 10. Install air bladder over outer tube by folding upward over tube and push over tube. 11. Install and tighten hose clamp over grooved area of air bladder. 12. Support strut and partially inflate air bladder. Check for leaks with soap solution. 13. Install strut into vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Wheel Bearing > Component Information > Adjustments Wheel Bearing: Adjustments FRONT WHEEL BEARINGS ADJUSTMENT Fig. 2 Front Wheel Bearing Adjustment 1. While rotating wheel forward, torque spindle nut to 12 ft. lbs., Fig. 2. 2. Back off nut until just loose then hand tighten nut and back it off again until either hole in spindle lines up with hole in nut. Do not back off nut more than 1/2 flat. 3. Install new cotter pin. With wheel bearing properly adjusted, there will be .001-.005 inch end play. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Suspension > Wheel Bearing > Component Information > Adjustments > Page 7796 Wheel Bearing: Service and Repair FRONT WHEEL BEARINGS Fig. 3 Hub & Wheel Bearing Replacement 1. Raise car and remove front wheels. 2. On models equipped with anti-lock brake systems, remove right and left wheel speed sensors as follows: a. Under vehicle hood, disconnect speed sensor electrical harness. b. Raise and support vehicle, then remove speed sensor harness bracket attaching bolt. c. Remove speed sensor to steering knuckle attaching bolt, then remove speed sensor and bracket assembly and position aside. d. Reverse procedure to install. Install wheel speed sensors by hand. Do not hammer sensors into position, as damage may result. 3. On all models, remove bolts holding brake caliper to its mounting and insert a fabricated block (11/16 x 1 1/16 x 2 inches in length) between brake pads as caliper is being removed. Once removed, caliper can be wired or secured in some manner away from disc. 4. Remove spindle nut and hub and disc assembly. Grease retainer and inner wheel bearing can now be removed, Fig. 3. 5. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Vehicle Lifting > Component Information > Service and Repair Vehicle Lifting: Service and Repair Vehicle Lift Points Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires Tires: Technical Service Bulletins Wheels/Tires - Use of Nitrogen Gas in Tires INFORMATION Bulletin No.: 05-03-10-020C Date: April 27, 2010 Subject: Use of Nitrogen Gas in Tires Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 05-03-10-020B (Section 03 - Suspension). GM's Position on the Use of Nitrogen Gas in Tires General Motors does not oppose the use of purified nitrogen as an inflation gas for tires. We expect the theoretical benefits to be reduced in practical use due to the lack of an existing infrastructure to continuously facilitate inflating tires with nearly pure nitrogen. Even occasional inflation with compressed atmospheric air will negate many of the theoretical benefits. Given those theoretical benefits, practical limitations, and the robust design of GM original equipment TPC tires, the realized benefits to our customer of inflating their tires with purified nitrogen are expected to be minimal. The Promise of Nitrogen: Under Controlled Conditions Recently, nitrogen gas (for use in inflating tires) has become available to the general consumer through some retailers. The use of nitrogen gas to inflate tires is a technology used in automobile racing. The following benefits under controlled conditions are attributed to nitrogen gas and its unique properties: - A reduction in the expected loss of Tire Pressure over time. - A reduction in the variance of Tire Pressures with temperature changes due to reduction of water vapor concentration. - A reduction of long term rubber degradation due to a decrease in oxygen concentrations. Important These are obtainable performance improvements when relatively pure nitrogen gas is used to inflate tires under controlled conditions. The Promise of Nitrogen: Real World Use Nitrogen inflation can provide some benefit by reducing gas migration (pressure loss) at the molecular level through the tire structure. NHTSA (National Highway Traffic Safety Administration) has stated that the inflation pressure loss of tires can be up to 5% a month. Nitrogen molecules are larger than oxygen molecules and, therefore, are less prone to "seeping" through the tire casing. The actual obtainable benefits of nitrogen vary, based on the physical construction and the materials used in the manufacturing of the tire being inflated. Another potential benefit of nitrogen is the reduced oxidation of tire components. Research has demonstrated that oxygen consumed in the oxidation process of the tire primarily comes from the inflation media. Therefore, it is reasonable to assume that oxidation of tire components can be reduced if the tire is inflated with pure nitrogen. However, only very small amounts of oxygen are required to begin the normal oxidation process. Even slight contamination of the tire inflation gas with compressed atmospheric air during normal inflation pressure maintenance, may negate the benefits of using nitrogen. GM Tire Quality, Technology and Focus of Importance Since 1972, General Motors has designed tires under the TPC (Tire Performance Criteria) specification system, which includes specific requirements that ensure robust tire performance under normal usage. General Motors works with tire suppliers to design and manufacture original equipment tires for GM vehicles. The GM TPC addresses required performance with respect to both inflation pressure retention, and endurance properties for original equipment tires. The inflation pressure retention requirements address availability of oxygen and oxidation concerns, while endurance requirements ensure the mechanical structure of the tire has sufficient strength. This combination has provided our customers with tires that maintain their structural integrity throughout their useful treadlife under normal operating conditions. Regardless of the inflation media for tires (atmospheric air or nitrogen), inflation pressure maintenance of tires is critical for overall tire, and ultimately, vehicle performance. Maintaining the correct inflation pressure allows the tire to perform as intended by the vehicle manufacturer in many areas, including comfort, fuel economy, stopping distance, cornering, traction, treadwear, and noise. Since the load carrying capability of a tire is related to inflation pressure, proper inflation pressure maintenance is necessary for the tire to support the load imposed by the vehicle without excessive structural Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7805 degradation. Important Regardless of the inflation media for tires (atmospheric air or nitrogen), inflation pressure maintenance of tires is critical for overall tire, and ultimately, vehicle performance. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7806 Tires: Technical Service Bulletins Tires/Wheels - Tire Puncture Repair Procedures INFORMATION Bulletin No.: 04-03-10-001F Date: April 27, 2010 Subject: Tire Puncture Repair Procedures For All Cars and Light Duty Trucks Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 04-03-10-001E (Section 03 - Suspension). This bulletin covers puncture repair procedures for passenger car and light duty truck radial tires in the tread area only. The tire manufacturer must be contacted for its individual repair policy and whether or not the speed rating is retained after repair. Caution - Tire changing can be dangerous and should be done by trained professionals using proper tools and procedures. Always read and understand any manufacturer's warnings contained in their customers literature or molded into the tire sidewall. - Serious eye and ear injury may result from not wearing adequate eye and ear protection while repairing tires. - NEVER inflate beyond 275 kPa (40 pounds) pressure to seat beads. Some run flat tires, such as the Goodyear Extended Mobility Tire (EMT) used on the Corvette, may require more than 275 kPa (40 psi) to seat the bead. In such a case, a tire safety cage must be used. Consult the tire manufacturer for its individual repair policy. - NEVER stand, lean or reach over the assembly during inflation. Repairable area on a radial tire. Important - NEVER repair tires worn to the tread indicators 1.59 mm (2/32") remaining depth). - NEVER repair tires with a tread puncture larger than 6.35 mm (1/4"). - NEVER substitute an inner tube for a permissible or non-permissible repair. - NEVER perform an outside-in tire repair (plug only, on the wheel). - Every tire must be removed from the wheel for proper inspection and repair. - Regardless of the type of repair used, the repair must seal the inner liner and fill the injury. - Consult with repair material supplier/manufacturer for repair unit application procedures and repair tools/repair material recommendations. Three basic steps for tire puncture repair: 1. Remove the tire from the wheel for inspection and repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7807 2. Fill the injury (puncture) to keep moisture out. 3. Seal the inner liner with a repair unit to prevent air loss. External Inspection 1. Prior to demounting, inspect the tire surface, the valve and the wheel for the source of the leak by using a water and soap solution. Mark the injured area and totally deflate the tire by removing the valve core. 2. Demount the tire from the wheel and place the tire on a well-lighted spreader. Internal Inspection 1. Spread the beads and mark the puncture with a tire crayon. 2. Inspect the inner tire for any signs of internal damage. 3. Remove the puncturing object, noting the direction of the penetration. 4. Probe the injury with a blunt awl in order to determine the extent and direction of the injury. 5. Remove any loose foreign material from the injury. 6. Punctures exceeding 6.35 mm (1/4") should not be repaired. Cleaning 1. Clean the area around the puncture thoroughly with a proper liner cleaner, clean cloth and a scraper. This step serves to remove dirt and mold lubricants to insure proper adhesion and non-contamination of the buffing tool. 2. Refer to information on the product or manufacturer's Material Safety Data Sheet and follow guidelines for handling and disposal. Clean the Injury Channel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7808 1. Use a proper hand reamer, carbide cutter or drill bit to ream the puncture channel from the inside of the tire in order to clean the injury. 2. Remove steel wires protruding above the liner surface to prevent damage to the repair unit. 3. Consult your repair material supplier for recommended reaming tool(s). Fill the Injury 1. It is necessary to fill the injury channel to provide back up for the repair unit and to prevent moisture from entering the tire fabric and steel wires. 2. (For combination repair/plug units skip this step.) Cement the injured channel and fill the injury from the inside of the tire with the repair plug per repair material manufacturer's recommendations. Without stretching the plug, cut the plug off just above the inside tire surface. 3. Consult your repair material supplier for proper repair material selection. Repair Unit Selection Important Do not install the repair unit in this step. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7809 1. Center the repair unit over the injury as a reference and outline an area larger than the unit so that buffing will not remove the crayon marks. 2. Remove the repair unit. 3. DO NOT overlap previous or multiple repair units. 4. Consult your repair material supplier for proper repair unit selection. Buffing 1. To prevent contamination and preserve the outline, buff within the marked area thoroughly and evenly with a low speed buffing tool using a fine wire brush or gritted rasp. 2. Buff to a smooth velvet surface (RMA #1 or #2 buffed texture). 3. Use caution not to gouge the inner liner or expose casing fabric. 4. Remove any buffing dust with a vacuum cleaner. 5. Consult your repair material supplier for a proper buffing tool. Cementing Apply chemical cement according to the repair material manufacturer's procedures. Repair Unit Application Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7810 1. The tire must be in the relaxed position when the repair unit is installed (Do not spread the beads excessively). Two-Piece Plug and Repair Units 1. If applicable, install the repair unit so that the alignment is correct. 2. Center the repair unit over the injury and stitch down thoroughly with the stitching tool, working from the center out. 3. Being careful not to stretch the plug material, cut the plug flush with the outer tread. Combination Repair/Plug Units 1. Pull the plug through the injury until the repair just reaches the liner. Stitch down thoroughly. 2. Follow the repair material manufacturer's recommendations for further installation instructions. 2. Consult your repair material supplier for the proper stitching tool. Safety Cage Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7811 Some run flat tires, such as the Goodyear Extended Mobility Tire (EMT) used on the Corvette, may require more than 275 kPa (40 psi) to seat the bead. In such a case, a tire safety cage must be used. Consult the tire manufacturer for its individual repair policy. Final Inspection 1. After remounting and inflating the tire, check both beads, the repair and the valve with a water and soap solution in order to detect leaks. 2. If the tire continues to lose air, the tire must be demounted and reinspected. 3. Balance the tire and wheel assembly. Refer to Tire and Wheel Assembly Balancing - OFF Vehicle. For additional tire puncture repair information, contact: Rubber Manufacturers Association (RMA) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7812 Tires: Technical Service Bulletins Tires - Correct Inflation Pressure Information INFORMATION Bulletin No.: 00-00-90-002J Date: January 28, 2009 Subject: Information on Proper Tire Pressure Models: 2010 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2009 and Prior HUMMER H2, H3, H3T 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add model years and clarify additional information. Please discard Corporate Bulletin Number 00-00-90-002I (Section 00 - General Information). Important: ^ Adjustment of tire pressure for a customer with a Low Tire Pressure Monitor (TPM) light on and no codes in the TPM system is NOT a warrantable repair. Claims to simply adjust the tire pressure will be rejected. ^ ALL tires (including the spare tire) MUST be set to the recommended inflation pressure stated on the vehicle's tire placard (on driver's door) during the PRE-DELIVERY INSPECTION (PDI). Recommended inflation pressure is not the pressure printed on tire sidewall. ^ Tires may be over-inflated from the assembly plant due to the mounting process. ^ Generally a 5.6°C (10°F) temperature change will result in (is equivalent to) a 6.9 kPa (1 psi) tire pressure change. ^ 2008-2009 HUMMER H2 Only - The H2 comes standard with Light Truck "D" Load Range tires with a recommended cold inflation pressure of 289 kPa (42 psi). These tires will alert the driver to a low pressure situation at roughly 262 kPa (38 psi) due to a requirement in FMVSS 138 which specifies a Minimum Activation Pressure for each tire type. This creates a relatively narrow window of "usable" pressure values and the warning will be more sensitive to outside temperature changes during the colder months. As with other cold temperature/tire pressure issues, there is nothing wrong with the system itself. If a vehicle is brought in with this concern, check for tire damage and set all tires to the Recommended Cold Inflation Pressure shown on the vehicle placard. Accurate tire pressures ensure the safe handling and appropriate ride characteristics of GM cars and trucks. It is critical that the tire pressure be adjusted to the specifications on the vehicle¡C■s tire placard during PDI. Ride, handling and road noise concerns may be caused by improperly adjusted tire pressure. The first step in the diagnosis of these concerns is to verify that the tires are inflated to the correct pressures. The recommended tire inflation pressure is listed on the vehicle¡C■s tire placard. The tire placard is located on the driver¡C■s side front or rear door edge, center pillar, or the rear compartment lid. Tip ^ Generally a 5.6°C (10°F) temperature increase will result in (is equivalent to) a 6.9 kPa (1 psi) tire pressure increase. ^ The definition of a "cold" tire is one that has been sitting for at least 3 hours, or driven no more than 1.6 km (1 mi). ^ On extremely cold days, if the vehicle has been indoors, it may be necessary to compensate for the low external temperature by adding additional air to the tire during PDI. ^ During cold weather, the Tire Pressure Monitor (TPM) indicator light (a yellow horseshoe with an exclamation point) may illuminate. If this indicator turns off after the tires warm up (reach operating temperature), the tire pressure should be reset to placard pressure at the cold temperature. ^ The TPM system will work correctly with nitrogen in tires. ^ The TPM system is compatible with the GM Vehicle Care Tire Sealant but may not be with other commercially available sealants. Important: ^ Do not use the tire pressure indicated on the tire itself as a guide. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Wheels/Tires - Use of Nitrogen Gas in Tires > Page 7813 ^ Always inspect and adjust the pressure when the tires are cold. ^ Vehicles that have different pressures for the front and the rear need to be adjusted after tire rotation. Improper tire inflation may result in any or all of the following conditions: ^ Premature tire wear ^ Harsh ride ^ Excessive road noise ^ Poor handling ^ Reduced fuel economy ^ Low Tire Pressure Monitor (TPM) Light ON ^ Low Tire Pressure Message on the Drivers Information Center (DIC) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Tires > Component Information > Technical Service Bulletins > Page 7814 Tires: Specifications Front .................................................................................................................................................... ......................................................... 210 kPa (30 psi) Rear ................................................................ .............................................................................................................................................. 210 kPa (30 psi) Full-Size Spare ....................................................................................................................... ...................................................................... 240 kPa (35 psi) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) Wheels: Customer Interest Wheels/Tires - Tire Radial Force Variation (RFV) INFORMATION Bulletin No.: 00-03-10-006F Date: May 04, 2010 Subject: Information on Tire Radial Force Variation (RFV) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X 2000-2005 Saturn L Series 2003-2007 Saturn ION Supercede: This bulletin is being revised to considerably expand the available information on Radial Force Variation (RFV) and should be reviewed in whole. Please discard Corporate Bulletin Number 00-03-10-006E (Section 03 - Suspension). Important - Before measuring tires on equipment such as the Hunter GSP9700, the vehicle MUST be driven a minimum of 16 km (10 mi) to ensure removal of any flat-spotting. Refer to Corporate Bulletin Number 03-03-10-007E - Tire/Wheel Characteristics of GM Original Equipment Tires. - Equipment such as the Hunter GSP9700 MUST be calibrated prior to measuring tire/wheel assemblies for each vehicle. The purpose of this bulletin is to provide guidance to GM dealers when using tire force variation measurement equipment, such as the Hunter GSP9700. This type of equipment can be a valuable tool in diagnosing vehicle ride concerns. The most common ride concern involving tire radial force variation is highway speed shake on smooth roads. Tire related smooth road highway speed shake can be caused by three conditions: imbalance, out of round and tire force variation. These three conditions are not necessarily related. All three conditions must be addressed. Imbalance is normally addressed first, because it is the simpler of the three to correct. Off-vehicle, two plane dynamic wheel balancers are readily available and can accurately correct any imbalance. Balancer calibration and maintenance, proper attachment of the wheel to the balancer, and proper balance weights, are all factors required for a quality balance. However, a perfectly balanced tire/wheel assembly can still be "oval shaped" and cause a vibration. Before balancing, perform the following procedures. Tire and Wheel Diagnosis 1. Set the tire pressure to the placard values. 2. With the vehicle raised, ensure the wheels are centered on the hub by loosening all wheel nuts and hand-tightening all nuts first by hand while shaking the wheel, then torque to specifications using a torque wrench, NOT a torque stick. 3. Visually inspect the tires and the wheels. Inspect for evidence of the following conditions and correct as necessary: - Missing balance weights - Bent rim flange - Irregular tire wear - Incomplete bead seating - Tire irregularities (including pressure settings) - Mud/ice build-up in wheel - Stones in the tire tread - Remove any aftermarket wheels and/or tires and restore vehicle to original condition prior to diagnosing a smooth road shake condition. 4. Road test the vehicle using the Electronic Vibration Analyzer (EVA) essential tool. Drive for a sufficient distance on a known, smooth road surface to duplicate the condition. Determine if the vehicle is sensitive to brake apply. If the brakes are applied lightly and the pulsation felt in the steering wheel increases, refer to the Brakes section of the service manual that deals with brake-induced pulsation. If you can start to hear the vibration as a low boom noise (in addition to feeling it), but cannot see it, the vehicle likely has a first order (one pulse per propshaft revolution) driveline vibration. Driveline first order vibrations are high enough in frequency that most humans can start to hear them at highway speeds, but are too high to be able to be easily seen. These issues can be caused by driveline imbalance or misalignment. If the vehicle exhibits this low boom and the booming pulses in-and-out on a regular basis (like a throbbing), chances are good that the vehicle could have driveline vibration. This type Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 7823 of vibration is normally felt more in the "seat of the pants" than the steering wheel. 5. Next, record the Hertz (Hz) reading as displayed by the EVA onto the tire data worksheet found at the end of this bulletin. This should be done after a tire break-in period of at least 16 km (10 mi) at 72 km/h (45 mph) or greater, in order to eliminate any possible tire flat-spotting. This reading confirms what the vehicle vibration frequency is prior to vehicle service and documents the amount of improvement occurring as the result of the various steps taken to repair. Completing the Steering Wheel Shake Worksheet below is required. A copy of the completed worksheet must be saved with the R.O. and a copy included with any parts returned to the Warranty Parts Center for analysis. A reading of 35 to 50 Hz typically indicates a first order propshaft vibration. If this is the situation, refer to Corporate Bulletin Number 08-07-30-044D. Generally, a reading between 10 and 20 Hz indicates a tire/wheel vibration and if this is the reading obtained, continue using this bulletin. If the tire 1st order vibration goes away and stays away during this evaluation, the cause is likely tire flat-spotting. Tire flat-spotting vibration may come and go at any speed over 72 km/h (45 mph) during the first 10 minutes of operation, if vibration continues after 10 minutes of driving at speeds greater than 72 km/h (45 mph), tire flat-spotting can be ruled out as the cause for vibration. 6. If flat-spotting is the cause, provide the explanation that this has occurred due to the vehicle being parked for long periods of time and that the nature of the tire is to take a set. Refer to Corporate Bulletin Number 03-03-10-007E: Information on Tire/Wheel Characteristics (Vibration, Balance, Shake, Flat Spotting) of GM Original Equipment Tires. 7. If the road test indicates a shake/vibration exists, check the imbalance of each tire/wheel assembly on a known, calibrated, off-car dynamic balancer.Make sure the mounting surface of the wheel and the surface of the balancer are absolutely clean and free of debris. Be sure to chose the proper cone/collet for the wheel, and always use the pilot bore for centering. Never center the wheel using the hub-cap bore since it is not a precision machined surface. If any assembly calls for more than 1/4 ounce on either rim flange, remove all balance weights and rebalance to as close to zero as possible. If you can see the vibration (along with feeling it) in the steering wheel (driving straight without your hands on the wheel), it is very likely to be a tire/wheel first order (one pulse per revolution) disturbance. First order disturbances can be caused by imbalance as well as non-uniformities in tires, wheels or hubs. This first order frequency is too low for a human to hear, but if the amplitude is high enough, it can be seen. If a vibration or shake still exists after balancing, any out of round conditions, of the wheel, and force variation conditions of the tire, must be addressed. Equipment such as the Hunter GSP9700 can address both (it is also a wheel balancer). Tire radial force vibration (RFV) can be defined as the amount of stiffness variation the tire will produce in one revolution under a constant load. Radial force variation is what the vehicle feels because the load (weight) of the vehicle is always on the tires. Although free runout of tires (not under load) is not always a good indicator of a smooth ride, it is critical that total tire/wheel assembly runout be within specification. Equipment such as the Hunter GSP9700 loads the tire, similar to on the vehicle, and measures radial force variation of the tire/wheel assembly. Note that the wheel is affecting the tire's RFV measurement at this point. To isolate the wheel, its runout must be measured. This can be easily done on the Hunter, without the need to set up dial indicators. If the wheel meets the runout specification, the tire's RFV can then be addressed. After measuring the tire/wheel assembly under load, and the wheel alone, the machine then calculates (predicts) the radial force variation of the tire. However, because this is a prediction that can include mounting inaccuracies, and the load wheel is much smaller in diameter than used in tire production, this type of service equipment should NOT be used to audit new tires. Rather, it should be used as a service diagnostic tool to minimize radial force variation of the tire/wheel assembly. Equipment such as the Hunter GSP9700 does an excellent job of measuring wheel runout, and of finding the low point of the wheel (for runout) and the high point of the tire (for radial force variation). This allows the tire to be matched mounted to the wheel for lowest tire/wheel assembly force variation. The machine will simplify this process into easy steps. The following assembly radial force variation numbers should be used as a guide: When measuring RFV and match mounting tires perform the following steps. Measuring Wheel Runout and Assembly Radial Force Variation Important The completed worksheet at the end of this bulletin must be attached to the hard copy of the repair order. - Measure radial force variation and radial runout. - If a road force/balancing machine is used, record the radial force variation (RFV) on the worksheet at the end of this bulletin. It may be of benefit to have the lowest RFV assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires onto the subject vehicle. - If a runout/balancing machine is used, record the radial runout of the tire/wheel assemblies on the worksheet at the end of this bulletin. If one or more of the tire/wheel assemblies are more than.040 in (1.02 mm), match mount the tire to the wheel to get below.040 in (1.02 mm). For sensitive customers, readings of 0.030 inch (0.76 mm) or less are preferable, it may also be of benefit to have the lowest runout assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 7824 onto the subject vehicle. - After match mounting, the tire/wheel assembly must be rebalanced. If match mounting tires to in-spec wheels produces assembly values higher than these, tire replacement may be necessary. Replacing tires at lower values will probably mean good tires are being condemned. Because tires can sometimes become temporarily flat-spotted, which will affect force variation, it is important that the vehicle be driven at least 16 km (10 mi) prior to measuring. Tire pressure must also be adjusted to the usage pressure on the vehicle's tire placard prior to measuring. Most GM vehicles will tolerate radial force variation up to these levels. However, some vehicles are more sensitive, and may require lower levels. Also, there are other tire parameters that equipment such as the Hunter GSP9700 cannot measure that may be a factor. In such cases, TAC should be contacted for further instructions. Important - When mounting a GM wheel to a wheel balancer/force variation machine, always use the wheel's center pilot hole. This is the primary centering mechanism on all GM wheels; the bolt holes are secondary. Usually a back cone method to the machine should be used. For added accuracy and repeatability, a flange plate should be used to clamp the wheel onto the cone and machine. This system is offered by all balancer manufacturers in GM's dealer program. - Any type of service equipment that removes tread rubber by grinding, buffing or truing is NOT recommended, and may void the tire warranty. However, tires may have been ground by the tire company as part of their tire manufacturing process. This is a legitimate procedure. Steering Wheel Shake Worksheet When diagnosing vibration concerns, use the following worksheet in conjunction with the appropriate Vibration Analysis-Road testing procedure in the Vibration Correction sub-section in SI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 7825 Refer to the appropriate section of SI for specifications and repair procedures that are related to the vibration concern. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels Wheels: Customer Interest Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels TECHNICAL Bulletin No.: 05-03-10-003F Date: April 27, 2010 Subject: Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X with Cast Aluminum Wheels Supercede: This bulletin is being revised to update the model years and the bulletin reference information. Please discard Corporate Bulletin Number 05-03-10-003E (Section 03 - Suspension). Condition Some customers may comment on a low tire pressure condition. Diagnosis of the low tire pressure condition indicates an air leak through the cast aluminum wheel. Cause Porosity in the cast aluminum wheel may be the cause. Notice This bulletin specifically addresses issues related to the wheel casting that may result in an air leak. For issues related to corrosion of the wheel in service, please refer to Corporate Bulletin Number 08-03-10-006C - Tire Slowly Goes Flat, Tire Air Loss, Low Tire Pressure Warning Light Illuminated, Aluminum Wheel Bead Seat Corrosion (Clean and Resurface Wheel Bead Seat). Correction 1. Remove the tire and wheel assembly from the vehicle. Refer to the appropriate service procedure in SI. 2. Locate the leaking area by inflating the tire to 276 kPa (40 psi) and dipping the tire/wheel assembly in a water bath, or use a spray bottle with soap and water to locate the specific leak location. Important - If the porosity leak is located in the bead area of the aluminum rim (where the tire meets the rim), the wheel should be replaced. - If two or more leaks are located on one wheel, the wheel should be replaced. 3. If air bubbles are observed, mark the location. - If the leak location is on the tire/rubber area, refer to Corporate Bulletin Number 04-03-10-001F Tire Puncture Repair Procedures for All Cars and Light Duty Trucks. - If the leak is located on the aluminum wheel area, continue with the next step. 4. Inscribe a mark on the tire at the valve stem in order to indicate the orientation of the tire to the wheel. 5. Dismount the tire from the wheel. Refer to Tire Mounting and Dismounting. 6. Remove the tire pressure sensor. Refer to Tire Pressure Sensor removal procedure in SI. 7. Scuff the INSIDE rim surface at the leak area with #80 grit paper and clean the area with general purpose cleaner, such as 3M(R) General Purpose Adhesive Cleaner, P/N 08984, or equivalent. 8. Apply a 3 mm (0.12 in) thick layer of Silicone - Adhesive/Sealant, P/N 12378478 (in Canada, use 88900041), or equivalent, to the leak area. 9. Allow for the adhesive/sealant to dry. Notice Caution must be used when mounting the tire so as not to damage the sealer. Damaging the repair area may result in an air leak. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > Customer Interest: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels > Page 7830 10. Align the inscribed mark on the tire with the valve stem on the wheel. 11. Reinstall the Tire Pressure Sensor. Refer to Tire Pressure Sensor installation procedure in SI. 12. Mount the tire on the wheel. Refer to Tire Mounting and Dismounting. 13. Pressurize the tire to 276 kPa (40 psi) and inspect for leaks. 14. Adjust tire pressure to meet the placard specification. 15. Balance the tire/wheel assembly. Refer to Tire and Wheel Assembly Balancing - Off-Vehicle. 16. Install the tire and wheel assembly onto the vehicle. Refer to the appropriate service procedure in SI. Parts Information Warranty Information (excluding Saab U.S. Models) Important The Silicone - Adhesive/Sealant comes in a case quantity of six. ONLY charge warranty one tube of adhesive/sealant per wheel repair. For vehicles repaired under warranty, use: One leak repair per wheel. Warranty Information (Saab U.S. Models) For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Staining/Pitting/Corrosion INFORMATION Bulletin No.: 00-03-10-002F Date: April 21, 2011 Subject: Chemical Staining, Pitting, Corrosion and/or Spotted Appearance of Chromed Aluminum Wheels Models: 2012 and Prior GM Cars and Trucks Supercede: This bulletin is being revised to update model years, suggest additional restorative products and add additional corrosion information. Please discard Corporate Bulletin Number 00-03-10-002E (Section 03 - Suspension). Important You may give a copy of this bulletin to the customer. What is Chemical Staining of Chrome Wheels? Figure 1 Chemical staining in most cases results from acid based cleaners (refer to Figure 1 for an example). These stains are frequently milky, black, or greenish in appearance. They result from using cleaning solutions that contain acids on chrome wheels. Soap and water is usually sufficient to clean wheels. If the customer insists on using a wheel cleaner they should only use one that specifically states that it is safe for chromed wheels and does not contain anything in the following list. (Dealers should also survey any products they use during prep or normal cleaning of stock units for these chemicals.) - Ammonium Bifluoride (fluoride source for dissolution of chrome) - Hydrofluoric Acid (directly dissolves chrome) - Hydrochloric Acid (directly dissolves chrome) - Sodium Dodecylbenzenesulfonic Acid - Sulfamic Acid - Phosphoric Acid - Hydroxyacetic Acid Notice Many wheel cleaner instructions advise to take care to avoid contact with painted surfaces. Most customers think of painted surfaces as the fenders, quarter panels and other exterior sheet metal. Many vehicles have painted brake calipers. Acidic wheel cleaners may craze, crack, or discolor the paint on the brake calipers. Damage from wheel cleaners is not covered under the vehicle new car warranty. Soap and water applied with a soft brush is usually all that is required to clean the calipers. Whenever any wheel cleaner is used, it must be THOROUGHLY rinsed off of the wheel with clean, clear water. Special care must be taken to rinse under the hub cap, balance weights, wheel nuts, lug nut caps, between the wheel cladding and off the back side of the wheel. Wheels returned to the Warranty Parts Center (WPC) that exhibit damage from wheel cleaners most often have the damage around and under the wheel weight where the cleaner was incompletely flushed away. Notice Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 7836 Do not use cleaning solutions that contain hydrofluoric, oxalic and most other acids on chrome wheels (or any wheels). If the customer is unsure of the chemical make-up of a particular wheel cleaner, it should be avoided. For wheels showing signs of milky staining from acidic cleaners, refer to Customer Assistance and Instructions below. Warranty of Stained Chrome Wheels Stained wheels are not warrantable. Most acid based cleaners will permanently stain chrome wheels. Follow-up with dealers has confirmed that such cleaners were used on wheels that were returned to the Warranty Parts Center (WPC). Any stained wheels received by the WPC will be charged back to the dealership. To assist the customer, refer to Customer Assistance and Instructions below. Pitting or Spotted Appearance of Chrome Wheels Figure 2 A second type or staining or finish disturbance may result from road chemicals, such as calcium chloride used for dust control of unpaved roads. The staining will look like small pitting (refer to Figure 2). This staining will usually be on the leading edges of each wheel spoke, but may be uniformly distributed. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Important Road chemicals, such as calcium chloride used for dust control of unpaved roads, can also stain chrome wheels. The staining will look like small pitting. This staining will usually be on the leading edges of each wheel spoke. This is explained by the vehicle traveling in the forward direction while being splashed by the road chemical. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Warranty of Pitted or Spotted Chrome Wheels Wheels returned with pitting or spotting as a result of road chemicals may be replaced one time. Damage resulting from contact with these applied road chemicals is corrosive to the wheels finish and may cause damage if the wheels are not kept clean. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean if they are operating the vehicle in an area that applies calcium chloride or other dust controlling chemicals! "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). "Stardust" Corrosion of Chrome Wheels Figure 3 A third type of finish disturbance results from prolonged exposure to brake dust and resultant penetration of brake dust through the chrome. As brakes are applied hot particles of brake material are thrown off and tend to be forced through the leading edge of the wheel spoke windows by airflow. These Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 7837 hot particles embed themselves in the chrome layer and create a small pit. If the material is allowed to sit on the wheel while it is exposed to moisture or salt, it will corrode the wheel beneath the chrome leaving a pit or small blister in the chrome. Heavy brake dust build-up should be removed from wheels by using GM Chrome Cleaner and Polish, P/N 1050173 (in Canada use 10953013). For moderate cleaning, light brake dust build-up or water spots use GM Swirl Remover Polish, P/N 12377965 (in Canada, use Meguiars Plast-X(TM) Clear Plastic Cleaner and Polish #G12310C**). After cleaning, the wheel should be waxed using GM Cleaner Wax, P/N 12377966 (in Canada, use Meguiars Cleaner Wax #M0616C**), which will help protect the wheel from brake dust and reduce adhesion of any brake dust that gets on the wheel surface. For general maintenance cleaning, PEEK Metal Polish† may be used. It will clean and shine the chrome and leave behind a wax coating that may help protect the finish. Warranty of Stardust Corroded Chrome Wheels Wheels returned with pitting or spotting as a result of neglect and brake dust build-up may be replaced one time. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean and free of prolonged exposure to brake dust build-up. "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). Customer Assistance and Instructions GM has looked for ways customers may improve the appearance of wheels damaged by acidic cleaners. The following product and procedure has been found to dramatically improve the appearance of stained wheels. For wheels that have milky stains caused by acidic cleaners try the following: Notice THE 3M CHROME AND METAL POLISH REQUIRED FOR THIS PROCEDURE IS AN EXTREMELY AGGRESSIVE POLISH/CLEANER. THE WHEELS MUST BE CLEANED BEFORE APPLICATION TO AVOID SCRATCHING THE WHEEL SURFACE. THIS PRODUCT WILL REDUCE THE THICKNESS OF THE CHROME PLATING ON THE WHEEL AND IF USED INCORRECTLY OR EXCESSIVELY MAY REMOVE THE CHROME PLATING ALL TOGETHER, EXPOSING A LESS BRIGHT AND BRASSY COLORED SUB-LAYER. FOLLOW INSTRUCTIONS EXACTLY. 1. Wash the wheels with vigorously with soap and water. This step will clean and may reduce wheel staining. Flood all areas of the wheel with water to rinse. 2. Dry the wheels completely. Notice Begin with a small section of the wheel and with light pressure buff off polish and examine results. ONLY apply and rub with sufficient force and time to remove enough staining that you are satisfied with the results. Some wheels may be stained to the extent that you may only achieve a 50% improvement while others may be able to be restored to the original lustre. IN ALL CASES, only apply until the results are satisfactory. 3. Apply 3M Chrome and Metal Polish #39527* with a clean terry cloth towel. As you apply the polish, the staining will be diminished. 4. When dry, buff off the polish with a clean portion of the towel. 5. Repeat application of the 3M Chrome and Metal Polish until satisfied with the results. If continued applications fail to improve the appearance further discontinue use. This procedure will improve the appearance of the wheels and may, with repeated applications, restore the finish dramatically. For wheels that exhibit spotting from road chemicals the above procedure may marginally improve the condition but will not restore the finish or remove the pitting. In this type of staining the wheel finish has actually been removed in spots and no manner of cleaning will restore the finish. †*We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Parts Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 7838 *This product is currently available from 3M. To obtain information for your local retail location please call 3M at 1-888-364-3577. **This product is currently available from Meguiars (Canada). To obtain information for your local retail location please call Meguiars at 1-800-347-5700 or at www.meguiarscanada.com. ^ This product is currently available from Tri-Peek International. To obtain information for your local retail location please call Tri-Peek at 1-877-615-4272 or at www.tripeek.com. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires Refinishing Aluminum Wheels Wheels: All Technical Service Bulletins Wheels/Tires - Refinishing Aluminum Wheels INFORMATION Bulletin No.: 99-08-51-007E Date: March 17, 2011 Subject: Refinishing Aluminum Wheels Models: 2012 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 99-08-51-007D (Section 08 - Body and Accessories). This bulletin updates General Motor's position on refinishing aluminum wheels. GM does not endorse any repairs that involve welding, bending, straightening or re-machining. Only cosmetic refinishing of the wheel's coatings, using recommended procedures, is allowed. Evaluating Damage In evaluating damage, it is the GM Dealer's responsibility to inspect the wheel for corrosion, scrapes, gouges, etc. The Dealer must insure that such damage is not deeper than what can be sanded or polished off. The wheel must be inspected for cracks. If cracks are found, discard the wheel. Any wheels with bent rim flanges must not be repaired or refinished. Wheels that have been refinished by an outside company must be returned to the same vehicle. The Dealer must record the wheel ID stamp or the cast date on the wheel in order to assure this requirement. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. Aluminum Wheel Refinishing Recommendations - Chrome-plated aluminum wheels Re-plating these wheels is not recommended. - Polished aluminum wheels These wheels have a polyester or acrylic clearcoat on them. If the clearcoat is damaged, refinishing is possible. However, the required refinishing process cannot be performed in the dealer environment. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. - Painted aluminum wheels These wheels are painted using a primer, color coat, and clearcoat procedure. If the paint is damaged, refinishing is possible. As with polished wheels, all original coatings must be removed first. Media blasting is recommended. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for the re-painting of this type of wheel. - Bright, machined aluminum wheels These wheels have a polyester or acrylic clearcoat on them. In some cases, the recessed "pocket" areas of the wheel may be painted. Surface refinishing is possible. The wheel must be totally stripped by media blasting or other suitable means. The wheel should be resurfaced by using a sanding process rather than a machining process. This allows the least amount of material to be removed. Important Do not use any re-machining process that removes aluminum. This could affect the dimensions and function of the wheel. Painting is an option to re-clearcoating polished and bright machined aluminum wheels. Paint will better mask any surface imperfections and is somewhat more durable than clearcoat alone. GM recommends using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option, the body color may also be used. When using any of the painting options, it is recommended that all four wheels be refinished in order to maintain color uniformity. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for specific procedures and product recommendations. Refinisher's Responsibility - Outside Company Important Some outside companies are offering wheel refinishing services. Such refinished wheels will be permanently marked by the refinisher and are warranted by the refinisher. Any process that re-machines or otherwise re-manufactures the wheel should not be used. A refinisher's responsibility includes inspecting for cracks using the Zyglo system or the equivalent. Any cracked wheels must not be refinished. No welding, hammering or reforming of any kind is allowed. The wheel ID must be recorded and follow the wheel throughout the process in order to assure that the same wheel is returned. A plastic media blast may be used for clean up of the wheel. Hand and/or lathe sanding of the machined surface and the wheel window is allowed. Material removal, though, must be kept to a minimum. Re-machining of the wheel is not allowed. Paint and/or clear coat must not be present on the following surfaces: the nut chamfers, the wheel mounting surfaces and the wheel pilot hole. The refinisher must permanently ID stamp the wheel and warrant the painted/clearcoated surfaces for a minimum of one year or the remainder of the new vehicle warranty, whichever is Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires Refinishing Aluminum Wheels > Page 7843 longer. Important Whenever a wheel is refinished, the mounting surface and the wheel nut contact surfaces must not be painted or clearcoated. Coating these surfaces could affect the wheel nut torque. When re-mounting a tire on an aluminum wheel, coated balance weights must be used in order to reduce the chance of future cosmetic damage. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions Wheels: All Technical Service Bulletins Wheels - Changing Procedures/Precautions INFORMATION Bulletin No.: 06-03-10-010A Date: June 09, 2010 Subject: Information on Proper Wheel Changing Procedures and Cautions Models: 2011 and Prior GM Passenger Cars and Trucks 2010 and Prior HUMMER Models 2005-2009 Saab 9-7X 2005-2009 Saturn Vehicles Attention: Complete wheel changing instructions for each vehicle line can be found under Tire and Wheel Removal and Installation in Service Information (SI). This bulletin is intended to quickly review and reinforce simple but vital procedures to reduce the possibility of achieving low torque during wheel installation. Always refer to SI for wheel lug nut torque specifications and complete jacking instructions for safe wheel changing. Supercede: This bulletin is being revised to include the 2011 model year and update the available special tool list. Please discard Corporate Bulletin Number 06-03-10-010 (Section 03 Suspension). Frequency of Wheel Changes - Marketplace Driven Just a few years ago, the increasing longevity of tires along with greater resistance to punctures had greatly reduced the number of times wheels were removed to basically required tire rotation intervals. Today with the booming business in accessory wheels/special application tires (such as winter tires), consumers are having tire/wheel assemblies removed - replaced - or installed more than ever. With this increased activity, it opens up more of a chance for error on the part of the technician. This bulletin will review a few of the common concerns and mistakes to make yourself aware of. Proper Servicing Starts With the Right Tools The following tools have been made available to assist in proper wheel and tire removal and installation. - J 41013 Rotor Resurfacing Kit (or equivalent) - J 42450-A Wheel Hub Resurfacing Kit (or equivalent) Corroded Surfaces One area of concern is corrosion on the mating surfaces of the wheel to the hub on the vehicle. Excessive corrosion, dirt, rust or debris built up on these surfaces can mimic a properly tightened wheel in the service stall. Once the vehicle is driven, the debris may loosen, grind up or be washed away from water splash. This action may result in clearance at the mating surface of the wheel and an under-torqued condition. Caution Before installing a wheel, remove any buildup on the wheel mounting surface and brake drum or brake disc mounting surface. Installing wheels with poor metal-to-metal contact at the mounting surfaces can cause wheel nuts to loosen. This may cause a wheel to come off when the vehicle is moving, possibly resulting in a loss of control or personal injury. Whenever you remove the tire/wheel assemblies, you must inspect the mating surfaces. If corrosion is found, you should remove the debris with a die grinder equipped with a fine sanding pad, wire brush or cleaning disc. Just remove enough material to assure a clean, smooth mating surface. The J 41013 (or equivalent) can be used to clean the following surfaces: - The hub mounting surface - The brake rotor mounting surface - The wheel mounting surface Use the J 42450-A (or equivalent) to clean around the base of the studs and the hub. Lubricants, Grease and Fluids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 7848 Some customers may use penetrating oils, grease or other lubricants on wheel studs to aid in removal or installation. Always use a suitable cleaner/solvent to remove these lubricants prior to installing the wheel and tire assemblies. Lubricants left on the wheel studs may cause improper readings of wheel nut torque. Always install wheels to clean, dry wheel studs ONLY. Notice Lubricants left on the wheel studs or vertical mounting surfaces between the wheel and the rotor or drum may cause the wheel to work itself loose after the vehicle is driven. Always install wheels to clean, dry wheel studs and surfaces ONLY. Beginning with 2011 model year vehicles, put a light coating of grease, GM P/N 1051344 (in Canada, P/N 9930370), on the inner surface of the wheel pilot hole to prevent wheel seizure to the axle or bearing hub. Wheel Stud and Lug Nut Damage Always inspect the wheel studs and lug nuts for signs of damage from crossthreading or abuse. You should never have to force wheel nuts down the stud. Lug nuts that are damaged may not retain properly, yet give the impression of fully tightening. Always inspect and replace any component suspected of damage. Tip Always start wheel nuts by hand! Be certain that all wheel nut threads have been engaged BEFORE tightening the nut. Important If the vehicle has directional tread tires, verify the directional arrow on the outboard side of the tire is pointing in the direction of forward rotation. Wheel Nut Tightening and Torque Improper wheel nut tightening can lead to brake pulsation and rotor damage. In order to avoid additional brake repairs, evenly tighten the wheel nuts to the proper torque specification as shown for each vehicle in SI. Always observe the proper wheel nut tightening sequence as shown below in order to avoid trapping the wheel on the wheel stud threads or clamping the wheel slightly off center resulting in vibration. The Most Important Service You Provide While the above information is well known, and wheel removal so common, technicians run the risk of becoming complacent on this very important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 7849 service operation. A simple distraction or time constraint that rushes the job may result in personal injury if the greatest of care is not exercised. Make it a habit to double check your work and to always side with caution when installing wheels. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) Wheels: All Technical Service Bulletins Wheels/Tires - Tire Radial Force Variation (RFV) INFORMATION Bulletin No.: 00-03-10-006F Date: May 04, 2010 Subject: Information on Tire Radial Force Variation (RFV) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X 2000-2005 Saturn L Series 2003-2007 Saturn ION Supercede: This bulletin is being revised to considerably expand the available information on Radial Force Variation (RFV) and should be reviewed in whole. Please discard Corporate Bulletin Number 00-03-10-006E (Section 03 - Suspension). Important - Before measuring tires on equipment such as the Hunter GSP9700, the vehicle MUST be driven a minimum of 16 km (10 mi) to ensure removal of any flat-spotting. Refer to Corporate Bulletin Number 03-03-10-007E - Tire/Wheel Characteristics of GM Original Equipment Tires. - Equipment such as the Hunter GSP9700 MUST be calibrated prior to measuring tire/wheel assemblies for each vehicle. The purpose of this bulletin is to provide guidance to GM dealers when using tire force variation measurement equipment, such as the Hunter GSP9700. This type of equipment can be a valuable tool in diagnosing vehicle ride concerns. The most common ride concern involving tire radial force variation is highway speed shake on smooth roads. Tire related smooth road highway speed shake can be caused by three conditions: imbalance, out of round and tire force variation. These three conditions are not necessarily related. All three conditions must be addressed. Imbalance is normally addressed first, because it is the simpler of the three to correct. Off-vehicle, two plane dynamic wheel balancers are readily available and can accurately correct any imbalance. Balancer calibration and maintenance, proper attachment of the wheel to the balancer, and proper balance weights, are all factors required for a quality balance. However, a perfectly balanced tire/wheel assembly can still be "oval shaped" and cause a vibration. Before balancing, perform the following procedures. Tire and Wheel Diagnosis 1. Set the tire pressure to the placard values. 2. With the vehicle raised, ensure the wheels are centered on the hub by loosening all wheel nuts and hand-tightening all nuts first by hand while shaking the wheel, then torque to specifications using a torque wrench, NOT a torque stick. 3. Visually inspect the tires and the wheels. Inspect for evidence of the following conditions and correct as necessary: - Missing balance weights - Bent rim flange - Irregular tire wear - Incomplete bead seating - Tire irregularities (including pressure settings) - Mud/ice build-up in wheel - Stones in the tire tread - Remove any aftermarket wheels and/or tires and restore vehicle to original condition prior to diagnosing a smooth road shake condition. 4. Road test the vehicle using the Electronic Vibration Analyzer (EVA) essential tool. Drive for a sufficient distance on a known, smooth road surface to duplicate the condition. Determine if the vehicle is sensitive to brake apply. If the brakes are applied lightly and the pulsation felt in the steering wheel increases, refer to the Brakes section of the service manual that deals with brake-induced pulsation. If you can start to hear the vibration as a low boom noise (in addition to feeling it), but cannot see it, the vehicle likely has a first order (one pulse per propshaft revolution) driveline vibration. Driveline first order vibrations are high enough in frequency that most humans can start to hear them at highway speeds, but are too high to be able to be easily seen. These issues can be caused by driveline imbalance or misalignment. If the vehicle exhibits this low boom and the booming pulses in-and-out on a regular basis (like a throbbing), chances are good that the vehicle could have driveline vibration. This type Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 7854 of vibration is normally felt more in the "seat of the pants" than the steering wheel. 5. Next, record the Hertz (Hz) reading as displayed by the EVA onto the tire data worksheet found at the end of this bulletin. This should be done after a tire break-in period of at least 16 km (10 mi) at 72 km/h (45 mph) or greater, in order to eliminate any possible tire flat-spotting. This reading confirms what the vehicle vibration frequency is prior to vehicle service and documents the amount of improvement occurring as the result of the various steps taken to repair. Completing the Steering Wheel Shake Worksheet below is required. A copy of the completed worksheet must be saved with the R.O. and a copy included with any parts returned to the Warranty Parts Center for analysis. A reading of 35 to 50 Hz typically indicates a first order propshaft vibration. If this is the situation, refer to Corporate Bulletin Number 08-07-30-044D. Generally, a reading between 10 and 20 Hz indicates a tire/wheel vibration and if this is the reading obtained, continue using this bulletin. If the tire 1st order vibration goes away and stays away during this evaluation, the cause is likely tire flat-spotting. Tire flat-spotting vibration may come and go at any speed over 72 km/h (45 mph) during the first 10 minutes of operation, if vibration continues after 10 minutes of driving at speeds greater than 72 km/h (45 mph), tire flat-spotting can be ruled out as the cause for vibration. 6. If flat-spotting is the cause, provide the explanation that this has occurred due to the vehicle being parked for long periods of time and that the nature of the tire is to take a set. Refer to Corporate Bulletin Number 03-03-10-007E: Information on Tire/Wheel Characteristics (Vibration, Balance, Shake, Flat Spotting) of GM Original Equipment Tires. 7. If the road test indicates a shake/vibration exists, check the imbalance of each tire/wheel assembly on a known, calibrated, off-car dynamic balancer.Make sure the mounting surface of the wheel and the surface of the balancer are absolutely clean and free of debris. Be sure to chose the proper cone/collet for the wheel, and always use the pilot bore for centering. Never center the wheel using the hub-cap bore since it is not a precision machined surface. If any assembly calls for more than 1/4 ounce on either rim flange, remove all balance weights and rebalance to as close to zero as possible. If you can see the vibration (along with feeling it) in the steering wheel (driving straight without your hands on the wheel), it is very likely to be a tire/wheel first order (one pulse per revolution) disturbance. First order disturbances can be caused by imbalance as well as non-uniformities in tires, wheels or hubs. This first order frequency is too low for a human to hear, but if the amplitude is high enough, it can be seen. If a vibration or shake still exists after balancing, any out of round conditions, of the wheel, and force variation conditions of the tire, must be addressed. Equipment such as the Hunter GSP9700 can address both (it is also a wheel balancer). Tire radial force vibration (RFV) can be defined as the amount of stiffness variation the tire will produce in one revolution under a constant load. Radial force variation is what the vehicle feels because the load (weight) of the vehicle is always on the tires. Although free runout of tires (not under load) is not always a good indicator of a smooth ride, it is critical that total tire/wheel assembly runout be within specification. Equipment such as the Hunter GSP9700 loads the tire, similar to on the vehicle, and measures radial force variation of the tire/wheel assembly. Note that the wheel is affecting the tire's RFV measurement at this point. To isolate the wheel, its runout must be measured. This can be easily done on the Hunter, without the need to set up dial indicators. If the wheel meets the runout specification, the tire's RFV can then be addressed. After measuring the tire/wheel assembly under load, and the wheel alone, the machine then calculates (predicts) the radial force variation of the tire. However, because this is a prediction that can include mounting inaccuracies, and the load wheel is much smaller in diameter than used in tire production, this type of service equipment should NOT be used to audit new tires. Rather, it should be used as a service diagnostic tool to minimize radial force variation of the tire/wheel assembly. Equipment such as the Hunter GSP9700 does an excellent job of measuring wheel runout, and of finding the low point of the wheel (for runout) and the high point of the tire (for radial force variation). This allows the tire to be matched mounted to the wheel for lowest tire/wheel assembly force variation. The machine will simplify this process into easy steps. The following assembly radial force variation numbers should be used as a guide: When measuring RFV and match mounting tires perform the following steps. Measuring Wheel Runout and Assembly Radial Force Variation Important The completed worksheet at the end of this bulletin must be attached to the hard copy of the repair order. - Measure radial force variation and radial runout. - If a road force/balancing machine is used, record the radial force variation (RFV) on the worksheet at the end of this bulletin. It may be of benefit to have the lowest RFV assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires onto the subject vehicle. - If a runout/balancing machine is used, record the radial runout of the tire/wheel assemblies on the worksheet at the end of this bulletin. If one or more of the tire/wheel assemblies are more than.040 in (1.02 mm), match mount the tire to the wheel to get below.040 in (1.02 mm). For sensitive customers, readings of 0.030 inch (0.76 mm) or less are preferable, it may also be of benefit to have the lowest runout assembly to the front left corner. If the machine is not available and the EVA data suggests there is an issue, swap the tire and wheel assemblies from the front to the back. Re-check on the EVA and if the problem still exists, test another vehicle to find tires that do not exhibit the same frequency and swap those tires Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 7855 onto the subject vehicle. - After match mounting, the tire/wheel assembly must be rebalanced. If match mounting tires to in-spec wheels produces assembly values higher than these, tire replacement may be necessary. Replacing tires at lower values will probably mean good tires are being condemned. Because tires can sometimes become temporarily flat-spotted, which will affect force variation, it is important that the vehicle be driven at least 16 km (10 mi) prior to measuring. Tire pressure must also be adjusted to the usage pressure on the vehicle's tire placard prior to measuring. Most GM vehicles will tolerate radial force variation up to these levels. However, some vehicles are more sensitive, and may require lower levels. Also, there are other tire parameters that equipment such as the Hunter GSP9700 cannot measure that may be a factor. In such cases, TAC should be contacted for further instructions. Important - When mounting a GM wheel to a wheel balancer/force variation machine, always use the wheel's center pilot hole. This is the primary centering mechanism on all GM wheels; the bolt holes are secondary. Usually a back cone method to the machine should be used. For added accuracy and repeatability, a flange plate should be used to clamp the wheel onto the cone and machine. This system is offered by all balancer manufacturers in GM's dealer program. - Any type of service equipment that removes tread rubber by grinding, buffing or truing is NOT recommended, and may void the tire warranty. However, tires may have been ground by the tire company as part of their tire manufacturing process. This is a legitimate procedure. Steering Wheel Shake Worksheet When diagnosing vibration concerns, use the following worksheet in conjunction with the appropriate Vibration Analysis-Road testing procedure in the Vibration Correction sub-section in SI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 00-03-10-006F > May > 10 > Wheels/Tires - Tire Radial Force Variation (RFV) > Page 7856 Refer to the appropriate section of SI for specifications and repair procedures that are related to the vibration concern. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels Wheels: All Technical Service Bulletins Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels TECHNICAL Bulletin No.: 05-03-10-003F Date: April 27, 2010 Subject: Low Tire Pressure, Leaking Cast Aluminum Wheels (Repair with Adhesive Sealant) Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X with Cast Aluminum Wheels Supercede: This bulletin is being revised to update the model years and the bulletin reference information. Please discard Corporate Bulletin Number 05-03-10-003E (Section 03 - Suspension). Condition Some customers may comment on a low tire pressure condition. Diagnosis of the low tire pressure condition indicates an air leak through the cast aluminum wheel. Cause Porosity in the cast aluminum wheel may be the cause. Notice This bulletin specifically addresses issues related to the wheel casting that may result in an air leak. For issues related to corrosion of the wheel in service, please refer to Corporate Bulletin Number 08-03-10-006C - Tire Slowly Goes Flat, Tire Air Loss, Low Tire Pressure Warning Light Illuminated, Aluminum Wheel Bead Seat Corrosion (Clean and Resurface Wheel Bead Seat). Correction 1. Remove the tire and wheel assembly from the vehicle. Refer to the appropriate service procedure in SI. 2. Locate the leaking area by inflating the tire to 276 kPa (40 psi) and dipping the tire/wheel assembly in a water bath, or use a spray bottle with soap and water to locate the specific leak location. Important - If the porosity leak is located in the bead area of the aluminum rim (where the tire meets the rim), the wheel should be replaced. - If two or more leaks are located on one wheel, the wheel should be replaced. 3. If air bubbles are observed, mark the location. - If the leak location is on the tire/rubber area, refer to Corporate Bulletin Number 04-03-10-001F Tire Puncture Repair Procedures for All Cars and Light Duty Trucks. - If the leak is located on the aluminum wheel area, continue with the next step. 4. Inscribe a mark on the tire at the valve stem in order to indicate the orientation of the tire to the wheel. 5. Dismount the tire from the wheel. Refer to Tire Mounting and Dismounting. 6. Remove the tire pressure sensor. Refer to Tire Pressure Sensor removal procedure in SI. 7. Scuff the INSIDE rim surface at the leak area with #80 grit paper and clean the area with general purpose cleaner, such as 3M(R) General Purpose Adhesive Cleaner, P/N 08984, or equivalent. 8. Apply a 3 mm (0.12 in) thick layer of Silicone - Adhesive/Sealant, P/N 12378478 (in Canada, use 88900041), or equivalent, to the leak area. 9. Allow for the adhesive/sealant to dry. Notice Caution must be used when mounting the tire so as not to damage the sealer. Damaging the repair area may result in an air leak. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 05-03-10-003F > Apr > 10 > Tires/Wheels - Low Tire/Leaking Cast Aluminum Wheels > Page 7861 10. Align the inscribed mark on the tire with the valve stem on the wheel. 11. Reinstall the Tire Pressure Sensor. Refer to Tire Pressure Sensor installation procedure in SI. 12. Mount the tire on the wheel. Refer to Tire Mounting and Dismounting. 13. Pressurize the tire to 276 kPa (40 psi) and inspect for leaks. 14. Adjust tire pressure to meet the placard specification. 15. Balance the tire/wheel assembly. Refer to Tire and Wheel Assembly Balancing - Off-Vehicle. 16. Install the tire and wheel assembly onto the vehicle. Refer to the appropriate service procedure in SI. Parts Information Warranty Information (excluding Saab U.S. Models) Important The Silicone - Adhesive/Sealant comes in a case quantity of six. ONLY charge warranty one tube of adhesive/sealant per wheel repair. For vehicles repaired under warranty, use: One leak repair per wheel. Warranty Information (Saab U.S. Models) For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 04-03-10-012B > Feb > 08 > Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Bulletin No.: 04-03-10-012B Date: February 01, 2008 INFORMATION Subject: Pitting and Brake Dust on Chrome wheels Models: 2008 and Prior GM Passenger Cars and Trucks (including Saturn) 2008 and Prior HUMMER H2, H3 2005-2008 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 04-03-10-012A (Section 03 - Suspension). Analysis of Returned Wheels Chrome wheels returned under the New Vehicle Limited Warranty for pitting concerns have recently been evaluated. This condition is usually most severe in the vent (or window) area of the front wheels. This "pitting" may actually be brake dust that has been allowed to accumulate on the wheel. The longer this accumulation builds up, the more difficult it is to remove. Cleaning the Wheels In all cases, the returned wheels could be cleaned to their original condition using GM Vehicle Care Cleaner Wax, P/N 12377966 (in Canada, P/N 10952905). When using this product, you should confine your treatment to the areas of the wheel that show evidence of the brake dust build-up. This product is only for use on chromed steel or chromed aluminum wheels. Parts Information Warranty Information Wheel replacement for this condition is NOT applicable under the terms of the New Vehicle Limited Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 99-03-10-102 > Jun > 99 > Warranty - OE Chrome Plated Aluminum Wheel ID Wheels: All Technical Service Bulletins Warranty - OE Chrome Plated Aluminum Wheel ID File In Section: 03 - Suspension Bulletin No.: 99-03-10-102 Date: June, 1999 INFORMATION Subject: Original Equipment Chrome Plated Aluminum Wheel Identification Models: 1999 and Prior Passenger Cars and Light Duty Trucks Chrome plated aluminum wheels have been returned to the Warranty Parts Center that are not the original equipment (OE) components. Original equipment chrome plated aluminum wheels can be identified by either a balance weight clip retention groove (1) or a step (2) that is machined around both of the wheel's rim flanges. The rim flanges (3) of painted original equipment aluminum wheels do not have a groove or a step. Chrome plated aluminum wheels that do not have the wheel rim flange groove or step are aftermarket chrome plated components and are NOT warrantable. Any aftermarket chrome wheels received by the Warranty Parts Center will be charged back to the dealership. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 72-05-05 > Aug > 97 > Warranty - Guidelines for Using E0420 Wheel Replace Wheels: All Technical Service Bulletins Warranty - Guidelines for Using E0420 Wheel Replace File In Section: Warranty Administration Bulletin No.: 72-05-05 Date: August, 1997 WARRANTY ADMINISTRATION Subject: Guidelines for Using EO42O Wheel Replace Models: 1989-98 Passenger Cars and Light Duty Trucks The purpose of this bulletin is to provide service personnel with guidelines for using the above subject labor operation. Effective with repair orders dated on or after September 1, 1997, dealers are to be guided by the following: ^ Aluminum Wheels (including chrome plated) with Porosity - Wheels that exhibit porosity should be repaired as described in the vehicle service manual. Wheels should not be replaced without wholesale approval. ^ Aluminum Wheels (except chrome plated) with a "Finish Defect" - Wheels that exhibit a defect in the finish, (i.e., discoloration or surface degradation) should be refinished as described in the Corporate Service Bulletin Number 53-17-03A released in May, 1996. ^ Chrome Wheels - Wheels that are chromed and found to have a finish defect can only be replaced. ^ Aluminum and chrome wheels replaced under warranty will be subject to random part review and inspection. Those wheels inspected and found not to be defective and/or should have been repaired, will be subject to charge back. Wheels damaged by normal wear, road hazards, car wash brushes, or other physical or chemical damage are not eligible for warranty coverage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing Technical Service Bulletin # 531703A Date: 960501 Aluminum Wheels - Refinishing File In Section: 10 - Body Bulletin No.: 53-17-03A Date: May, 1996 INFORMATION Subject: Aluminum Wheel Refinishing Models: 1991-96 Passenger Cars and Trucks This bulletin is being revised to delete the 1990 model year and add the 1996 model year. Please discard Corporate Bulletin Number 53-17-03 (Section 10 - Body). This bulletin supersedes and cancels all previous service bulletins concerning the refinishing of aluminum wheels. The purpose of this service bulletin is to assist dealerships in repairing the discoloration or surface degradation that has occurred on styled aluminum wheels. This bulletin provides NEW PROCEDURES AND SPECIFIC MATERIALS for the refinishing of painted aluminum wheels or aluminum wheels with discoloration or surface degradation. Important: THE RE-MACHINING OF ALUMINUM WHEELS IS NOT RECOMMENDED. THE RE-CLEAR COATING OF ALUMINUM WHEELS IS NO LONGER RECOMMENDED DUE TO CONCERNS OF REPAIR DURABILITY The new procedure requires the wheel surface be plastic media blasted to remove old paint or clear coat. CHEMICAL STRIPPERS ARE NOT RECOMMENDED. Material Required System 1: DuPont Products 3939-S Cleaning Solvent 615/616 Etching Primer URO 5000 Primer Surfacer IMRON 6000 Basecoat 3440-S IMRON Clear System 2: PPG Products DX533 Aluminum Cleaner DX503 Aluminum Conditioner DP Epoxy Primer Deltron Basecoat (DBC) Concept 2001 Clear Acrylic Urethane System 3: Spies Hecker Permahyd Silicone Remover 7090 Permahyd 1:1 Primer 4070 Permahyd 2:1 Surfacer 5080 Permahyd Base Coat Series 280/285 Permahyd H.S. Clearcoat 8060 Color Selection If the wheels being painted were previously clearcoated aluminum, we would recommend using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option to the customer, you may also use body color. For color Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing > Page 7878 selection and verification, refer to your paint manufacturer's color book. On wheels that were previous clearcoated aluminum it is recommended that all four wheels and their center caps be refinished to maintain color uniformity. Important: THE PRODUCTS LISTED MUST BE USED AS A SYSTEM. DO NOT MIX OTHER MANUFACTURERS' PRODUCT LINES WITH THE REQUIRED MATERIALS. PRODUCTS LISTED IN THIS BULLETIN HAVE SHOWN THE REQUIRED REPAIR DURABILITY, AND CURRENTLY ARE THE ONLY PAINT SYSTEMS THAT MEET GM SPECIFICATION 4350M-A336. Procedures 1. Remove wheels from vehicle. Tires may remain mounted on wheels. 2. Remove balance weights and mark their location on tire. 3. Wipe excess grease, etc. from wheels with wax and grease remover. 4. Have wheels plastic media blasted to remove clearcoat. FOR FURTHER INFORMATION ON MEDIA BLASTING IN YOUR AREA, CALL US TECHNOLOGIES INC., CONTACT DAVE ROSENBURG AT 1-800-634-9185. Caution: IT IS MANDATORY THAT ADEQUATE RESPIRATORY PROTECTION BE WORN. EXAMPLES OF SUCH PROTECTION ARE: AIR LINE RESPIRATORS WITH FULL HOOD OR HALF MASK. IF NOT AVAILABLE, USE A VAPOR/PARTICULATE RESPIRATOR THAT RESPIRATOR MANUFACTURER RECOMMENDS AS EFFECTIVE FOR ISOCYANATE VAPOR AND MISTS (UNLESS LOCAL REGULATIONS PREVAIL). 5. Painting Process a. Refer to Attachments 1-3 for each System's individual formula and process. b. After following the specific System's individual formula and process, follow these steps: 6. Unmask wheels. 7. Clean all wheel mounting surface of any corrosion, overspray, or dirt. 8. Install new coated balance weights, at marked locations. 9. Replace wheels on vehicle. 10. USE A TORQUE STICK ON AN IMPACT WRENCH, OR A TORQUE WRENCH TO CONSISTENTLY AND UNIFORMLY FASTEN THE WHEEL TO THE SPECIFIED TORQUE FOR THE VEHICLE. THE STAR PATTERN MUST BE FOLLOWED. Important: TORQUE STICKS MUST BE USED ANY TIME AN IMPACT WRENCH IS USED TO TIGHTEN WHEEL NUTS. Warranty Information For vehicles repaired under warranty, use as shown. Attachment 1 - DuPont Products Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing > Page 7879 Painting Process System: Dupont Products Paint Color Information: Corsican Silver WA EQ9283 Dupont # C9143, Sparkle Silver WA9967 Dupont # C9339 1. Wipe wheel with cleaning solvent: 3939-S, 3949-S or 3900-S. 2. Mask off tires. Important: 3. Mask off all wheel mounting surfaces and wheel mount surfaces. 4. Apply two coats of 615/616-S etching primer to wheel allowing 10 minutes flash between coats. Allow to dry for 30 minutes before applying primer coat. 5. Apply URO 5000 primer 1220/193-S + accelerator 389-S using two coats at 65-70 PSI at the gun. Allow 12-15 minutes between coats. Force bake 30 minutes at 140°F (60°C). 6. Scuff sand using green Scotch-Brite pad. 7. Solvent wipe before top coating. 8. Apply IMRON 6000 base coat to wheel. 2-3 coats to hiding at 60-70 PSI allowing to flash between coats. Base coat needs to dry 20-30 minutes before clearcoat is applied. 9. Apply 3440-S clearcoat to wheel using two coats at 60-70 PSI. Flash 10-15 minutes between coats. 389-S can be used in basecoat and clearcoat to give faster set up times. 10. Allow overnight dry before reassemble. Can be baked for 30 minutes at 140°F (60°C). Attachment 2 - PPG Products Painting Process: PPG System Paint Color Information: Corsican Silver WAEQ9283; PPG # DBC-3531, Sparkle Silver WA9967; PPG # 35367 1. Wash entire wheel with aluminum cleaner DX533, mix 1:3 with water. Allow to react 2-3 minutes and rinse thoroughly. 2. Wash entire wheel with aluminum conditioner DX5O3 straight from the container. Allow to react 2-3 minutes until pale gold or tan color develops. Rinse thoroughly and dry. 3. Mask off tires. Important: 4. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 5. Apply 1-2 coats of DP Primer and allow to flash for 15-20 minutes. 6. Apply 2-3 coats of Deltron Basecoat (DBC) and allow to flash 20 minutes after the final coat. 7. Apply two (2) wet coats of Concept 2001 Acrylic urethane. 8. Flash 20 minutes and bake 140°F (60°C) for 30 minutes. For more information contact your PPG Jobber. Attachment 3 - Spies Hecker Painting Process: Spies Hecker System Paint Color Information: Corsican Silver AWEQ9283; SH-72913, Sparkle Silver WA9967; SH-71912 1. Clean with Permahyd Silicone Remover 7090. 2. Mask off tires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing > Page 7880 Important: 3. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 4. Apply 1-1/2 coats of Permahyd 1:1 Primer 4070. Mix 1:1 with Permahyd Hardener 3070 as per TDS. 5. Allow to flash for 30 minutes. 6. Apply two (2) coats of Permahyd 2:1 Surfacer 5080. Mix 2:1 with Permahyd Hardener 3071 as per TDS. 7. Bake for 60 minutes at 140°F (60°C) or allow to flash for 3 hours at 68°F (20°C). 8. Apply Permahyd Base Coat Series 280/285 as per TDS. 9. Allow to flash 10 to 15 minutes. 10. Apply 1 to 2 coats of Permacron High Solid Clear Coat 8060 as per TDS. 11. Allow to flash 10 minutes. Then bake at 140°F (60°C) for 40 minutes. For more information, contact your SPIES HECKER Jobber. We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Staining/Pitting/Corrosion INFORMATION Bulletin No.: 00-03-10-002F Date: April 21, 2011 Subject: Chemical Staining, Pitting, Corrosion and/or Spotted Appearance of Chromed Aluminum Wheels Models: 2012 and Prior GM Cars and Trucks Supercede: This bulletin is being revised to update model years, suggest additional restorative products and add additional corrosion information. Please discard Corporate Bulletin Number 00-03-10-002E (Section 03 - Suspension). Important You may give a copy of this bulletin to the customer. What is Chemical Staining of Chrome Wheels? Figure 1 Chemical staining in most cases results from acid based cleaners (refer to Figure 1 for an example). These stains are frequently milky, black, or greenish in appearance. They result from using cleaning solutions that contain acids on chrome wheels. Soap and water is usually sufficient to clean wheels. If the customer insists on using a wheel cleaner they should only use one that specifically states that it is safe for chromed wheels and does not contain anything in the following list. (Dealers should also survey any products they use during prep or normal cleaning of stock units for these chemicals.) - Ammonium Bifluoride (fluoride source for dissolution of chrome) - Hydrofluoric Acid (directly dissolves chrome) - Hydrochloric Acid (directly dissolves chrome) - Sodium Dodecylbenzenesulfonic Acid - Sulfamic Acid - Phosphoric Acid - Hydroxyacetic Acid Notice Many wheel cleaner instructions advise to take care to avoid contact with painted surfaces. Most customers think of painted surfaces as the fenders, quarter panels and other exterior sheet metal. Many vehicles have painted brake calipers. Acidic wheel cleaners may craze, crack, or discolor the paint on the brake calipers. Damage from wheel cleaners is not covered under the vehicle new car warranty. Soap and water applied with a soft brush is usually all that is required to clean the calipers. Whenever any wheel cleaner is used, it must be THOROUGHLY rinsed off of the wheel with clean, clear water. Special care must be taken to rinse under the hub cap, balance weights, wheel nuts, lug nut caps, between the wheel cladding and off the back side of the wheel. Wheels returned to the Warranty Parts Center (WPC) that exhibit damage from wheel cleaners most often have the damage around and under the wheel weight where the cleaner was incompletely flushed away. Notice Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 7886 Do not use cleaning solutions that contain hydrofluoric, oxalic and most other acids on chrome wheels (or any wheels). If the customer is unsure of the chemical make-up of a particular wheel cleaner, it should be avoided. For wheels showing signs of milky staining from acidic cleaners, refer to Customer Assistance and Instructions below. Warranty of Stained Chrome Wheels Stained wheels are not warrantable. Most acid based cleaners will permanently stain chrome wheels. Follow-up with dealers has confirmed that such cleaners were used on wheels that were returned to the Warranty Parts Center (WPC). Any stained wheels received by the WPC will be charged back to the dealership. To assist the customer, refer to Customer Assistance and Instructions below. Pitting or Spotted Appearance of Chrome Wheels Figure 2 A second type or staining or finish disturbance may result from road chemicals, such as calcium chloride used for dust control of unpaved roads. The staining will look like small pitting (refer to Figure 2). This staining will usually be on the leading edges of each wheel spoke, but may be uniformly distributed. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Important Road chemicals, such as calcium chloride used for dust control of unpaved roads, can also stain chrome wheels. The staining will look like small pitting. This staining will usually be on the leading edges of each wheel spoke. This is explained by the vehicle traveling in the forward direction while being splashed by the road chemical. If a vehicle must be operated under such conditions, the chrome wheels should be washed with mild soap and water and thoroughly rinsed as soon as conveniently possible. Warranty of Pitted or Spotted Chrome Wheels Wheels returned with pitting or spotting as a result of road chemicals may be replaced one time. Damage resulting from contact with these applied road chemicals is corrosive to the wheels finish and may cause damage if the wheels are not kept clean. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean if they are operating the vehicle in an area that applies calcium chloride or other dust controlling chemicals! "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). "Stardust" Corrosion of Chrome Wheels Figure 3 A third type of finish disturbance results from prolonged exposure to brake dust and resultant penetration of brake dust through the chrome. As brakes are applied hot particles of brake material are thrown off and tend to be forced through the leading edge of the wheel spoke windows by airflow. These Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 7887 hot particles embed themselves in the chrome layer and create a small pit. If the material is allowed to sit on the wheel while it is exposed to moisture or salt, it will corrode the wheel beneath the chrome leaving a pit or small blister in the chrome. Heavy brake dust build-up should be removed from wheels by using GM Chrome Cleaner and Polish, P/N 1050173 (in Canada use 10953013). For moderate cleaning, light brake dust build-up or water spots use GM Swirl Remover Polish, P/N 12377965 (in Canada, use Meguiars Plast-X(TM) Clear Plastic Cleaner and Polish #G12310C**). After cleaning, the wheel should be waxed using GM Cleaner Wax, P/N 12377966 (in Canada, use Meguiars Cleaner Wax #M0616C**), which will help protect the wheel from brake dust and reduce adhesion of any brake dust that gets on the wheel surface. For general maintenance cleaning, PEEK Metal Polish† may be used. It will clean and shine the chrome and leave behind a wax coating that may help protect the finish. Warranty of Stardust Corroded Chrome Wheels Wheels returned with pitting or spotting as a result of neglect and brake dust build-up may be replaced one time. Important Notify the customer that this is a one time replacement. Please stress to the customer the vital importance of keeping the wheels clean and free of prolonged exposure to brake dust build-up. "GM of Canada" dealers require prior approval by the District Manager - Customer Care and Service Process (DM-CCSP). Customer Assistance and Instructions GM has looked for ways customers may improve the appearance of wheels damaged by acidic cleaners. The following product and procedure has been found to dramatically improve the appearance of stained wheels. For wheels that have milky stains caused by acidic cleaners try the following: Notice THE 3M CHROME AND METAL POLISH REQUIRED FOR THIS PROCEDURE IS AN EXTREMELY AGGRESSIVE POLISH/CLEANER. THE WHEELS MUST BE CLEANED BEFORE APPLICATION TO AVOID SCRATCHING THE WHEEL SURFACE. THIS PRODUCT WILL REDUCE THE THICKNESS OF THE CHROME PLATING ON THE WHEEL AND IF USED INCORRECTLY OR EXCESSIVELY MAY REMOVE THE CHROME PLATING ALL TOGETHER, EXPOSING A LESS BRIGHT AND BRASSY COLORED SUB-LAYER. FOLLOW INSTRUCTIONS EXACTLY. 1. Wash the wheels with vigorously with soap and water. This step will clean and may reduce wheel staining. Flood all areas of the wheel with water to rinse. 2. Dry the wheels completely. Notice Begin with a small section of the wheel and with light pressure buff off polish and examine results. ONLY apply and rub with sufficient force and time to remove enough staining that you are satisfied with the results. Some wheels may be stained to the extent that you may only achieve a 50% improvement while others may be able to be restored to the original lustre. IN ALL CASES, only apply until the results are satisfactory. 3. Apply 3M Chrome and Metal Polish #39527* with a clean terry cloth towel. As you apply the polish, the staining will be diminished. 4. When dry, buff off the polish with a clean portion of the towel. 5. Repeat application of the 3M Chrome and Metal Polish until satisfied with the results. If continued applications fail to improve the appearance further discontinue use. This procedure will improve the appearance of the wheels and may, with repeated applications, restore the finish dramatically. For wheels that exhibit spotting from road chemicals the above procedure may marginally improve the condition but will not restore the finish or remove the pitting. In this type of staining the wheel finish has actually been removed in spots and no manner of cleaning will restore the finish. †*We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Parts Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 00-03-10-002F > Apr > 11 > Wheels - Chrome Wheel Staining/Pitting/Corrosion > Page 7888 *This product is currently available from 3M. To obtain information for your local retail location please call 3M at 1-888-364-3577. **This product is currently available from Meguiars (Canada). To obtain information for your local retail location please call Meguiars at 1-800-347-5700 or at www.meguiarscanada.com. ^ This product is currently available from Tri-Peek International. To obtain information for your local retail location please call Tri-Peek at 1-877-615-4272 or at www.tripeek.com. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires Refinishing Aluminum Wheels Wheels: All Technical Service Bulletins Wheels/Tires - Refinishing Aluminum Wheels INFORMATION Bulletin No.: 99-08-51-007E Date: March 17, 2011 Subject: Refinishing Aluminum Wheels Models: 2012 and Prior GM Passenger Cars and Trucks Supercede: This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 99-08-51-007D (Section 08 - Body and Accessories). This bulletin updates General Motor's position on refinishing aluminum wheels. GM does not endorse any repairs that involve welding, bending, straightening or re-machining. Only cosmetic refinishing of the wheel's coatings, using recommended procedures, is allowed. Evaluating Damage In evaluating damage, it is the GM Dealer's responsibility to inspect the wheel for corrosion, scrapes, gouges, etc. The Dealer must insure that such damage is not deeper than what can be sanded or polished off. The wheel must be inspected for cracks. If cracks are found, discard the wheel. Any wheels with bent rim flanges must not be repaired or refinished. Wheels that have been refinished by an outside company must be returned to the same vehicle. The Dealer must record the wheel ID stamp or the cast date on the wheel in order to assure this requirement. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. Aluminum Wheel Refinishing Recommendations - Chrome-plated aluminum wheels Re-plating these wheels is not recommended. - Polished aluminum wheels These wheels have a polyester or acrylic clearcoat on them. If the clearcoat is damaged, refinishing is possible. However, the required refinishing process cannot be performed in the dealer environment. Refer to Refinisher's Responsibility - Outside Company later in this bulletin. - Painted aluminum wheels These wheels are painted using a primer, color coat, and clearcoat procedure. If the paint is damaged, refinishing is possible. As with polished wheels, all original coatings must be removed first. Media blasting is recommended. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for the re-painting of this type of wheel. - Bright, machined aluminum wheels These wheels have a polyester or acrylic clearcoat on them. In some cases, the recessed "pocket" areas of the wheel may be painted. Surface refinishing is possible. The wheel must be totally stripped by media blasting or other suitable means. The wheel should be resurfaced by using a sanding process rather than a machining process. This allows the least amount of material to be removed. Important Do not use any re-machining process that removes aluminum. This could affect the dimensions and function of the wheel. Painting is an option to re-clearcoating polished and bright machined aluminum wheels. Paint will better mask any surface imperfections and is somewhat more durable than clearcoat alone. GM recommends using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option, the body color may also be used. When using any of the painting options, it is recommended that all four wheels be refinished in order to maintain color uniformity. Refer to GM Aluminum Refinishing Bulletin #53-17-03A for specific procedures and product recommendations. Refinisher's Responsibility - Outside Company Important Some outside companies are offering wheel refinishing services. Such refinished wheels will be permanently marked by the refinisher and are warranted by the refinisher. Any process that re-machines or otherwise re-manufactures the wheel should not be used. A refinisher's responsibility includes inspecting for cracks using the Zyglo system or the equivalent. Any cracked wheels must not be refinished. No welding, hammering or reforming of any kind is allowed. The wheel ID must be recorded and follow the wheel throughout the process in order to assure that the same wheel is returned. A plastic media blast may be used for clean up of the wheel. Hand and/or lathe sanding of the machined surface and the wheel window is allowed. Material removal, though, must be kept to a minimum. Re-machining of the wheel is not allowed. Paint and/or clear coat must not be present on the following surfaces: the nut chamfers, the wheel mounting surfaces and the wheel pilot hole. The refinisher must permanently ID stamp the wheel and warrant the painted/clearcoated surfaces for a minimum of one year or the remainder of the new vehicle warranty, whichever is Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 99-08-51-007E > Mar > 11 > Wheels/Tires Refinishing Aluminum Wheels > Page 7893 longer. Important Whenever a wheel is refinished, the mounting surface and the wheel nut contact surfaces must not be painted or clearcoated. Coating these surfaces could affect the wheel nut torque. When re-mounting a tire on an aluminum wheel, coated balance weights must be used in order to reduce the chance of future cosmetic damage. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions Wheels: All Technical Service Bulletins Wheels - Changing Procedures/Precautions INFORMATION Bulletin No.: 06-03-10-010A Date: June 09, 2010 Subject: Information on Proper Wheel Changing Procedures and Cautions Models: 2011 and Prior GM Passenger Cars and Trucks 2010 and Prior HUMMER Models 2005-2009 Saab 9-7X 2005-2009 Saturn Vehicles Attention: Complete wheel changing instructions for each vehicle line can be found under Tire and Wheel Removal and Installation in Service Information (SI). This bulletin is intended to quickly review and reinforce simple but vital procedures to reduce the possibility of achieving low torque during wheel installation. Always refer to SI for wheel lug nut torque specifications and complete jacking instructions for safe wheel changing. Supercede: This bulletin is being revised to include the 2011 model year and update the available special tool list. Please discard Corporate Bulletin Number 06-03-10-010 (Section 03 Suspension). Frequency of Wheel Changes - Marketplace Driven Just a few years ago, the increasing longevity of tires along with greater resistance to punctures had greatly reduced the number of times wheels were removed to basically required tire rotation intervals. Today with the booming business in accessory wheels/special application tires (such as winter tires), consumers are having tire/wheel assemblies removed - replaced - or installed more than ever. With this increased activity, it opens up more of a chance for error on the part of the technician. This bulletin will review a few of the common concerns and mistakes to make yourself aware of. Proper Servicing Starts With the Right Tools The following tools have been made available to assist in proper wheel and tire removal and installation. - J 41013 Rotor Resurfacing Kit (or equivalent) - J 42450-A Wheel Hub Resurfacing Kit (or equivalent) Corroded Surfaces One area of concern is corrosion on the mating surfaces of the wheel to the hub on the vehicle. Excessive corrosion, dirt, rust or debris built up on these surfaces can mimic a properly tightened wheel in the service stall. Once the vehicle is driven, the debris may loosen, grind up or be washed away from water splash. This action may result in clearance at the mating surface of the wheel and an under-torqued condition. Caution Before installing a wheel, remove any buildup on the wheel mounting surface and brake drum or brake disc mounting surface. Installing wheels with poor metal-to-metal contact at the mounting surfaces can cause wheel nuts to loosen. This may cause a wheel to come off when the vehicle is moving, possibly resulting in a loss of control or personal injury. Whenever you remove the tire/wheel assemblies, you must inspect the mating surfaces. If corrosion is found, you should remove the debris with a die grinder equipped with a fine sanding pad, wire brush or cleaning disc. Just remove enough material to assure a clean, smooth mating surface. The J 41013 (or equivalent) can be used to clean the following surfaces: - The hub mounting surface - The brake rotor mounting surface - The wheel mounting surface Use the J 42450-A (or equivalent) to clean around the base of the studs and the hub. Lubricants, Grease and Fluids Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 7898 Some customers may use penetrating oils, grease or other lubricants on wheel studs to aid in removal or installation. Always use a suitable cleaner/solvent to remove these lubricants prior to installing the wheel and tire assemblies. Lubricants left on the wheel studs may cause improper readings of wheel nut torque. Always install wheels to clean, dry wheel studs ONLY. Notice Lubricants left on the wheel studs or vertical mounting surfaces between the wheel and the rotor or drum may cause the wheel to work itself loose after the vehicle is driven. Always install wheels to clean, dry wheel studs and surfaces ONLY. Beginning with 2011 model year vehicles, put a light coating of grease, GM P/N 1051344 (in Canada, P/N 9930370), on the inner surface of the wheel pilot hole to prevent wheel seizure to the axle or bearing hub. Wheel Stud and Lug Nut Damage Always inspect the wheel studs and lug nuts for signs of damage from crossthreading or abuse. You should never have to force wheel nuts down the stud. Lug nuts that are damaged may not retain properly, yet give the impression of fully tightening. Always inspect and replace any component suspected of damage. Tip Always start wheel nuts by hand! Be certain that all wheel nut threads have been engaged BEFORE tightening the nut. Important If the vehicle has directional tread tires, verify the directional arrow on the outboard side of the tire is pointing in the direction of forward rotation. Wheel Nut Tightening and Torque Improper wheel nut tightening can lead to brake pulsation and rotor damage. In order to avoid additional brake repairs, evenly tighten the wheel nuts to the proper torque specification as shown for each vehicle in SI. Always observe the proper wheel nut tightening sequence as shown below in order to avoid trapping the wheel on the wheel stud threads or clamping the wheel slightly off center resulting in vibration. The Most Important Service You Provide While the above information is well known, and wheel removal so common, technicians run the risk of becoming complacent on this very important Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 06-03-10-010A > Jun > 10 > Wheels - Changing Procedures/Precautions > Page 7899 service operation. A simple distraction or time constraint that rushes the job may result in personal injury if the greatest of care is not exercised. Make it a habit to double check your work and to always side with caution when installing wheels. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 04-03-10-012B > Feb > 08 > Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Wheels: All Technical Service Bulletins Wheels - Chrome Wheel Brake Dust Accumulation/Pitting Bulletin No.: 04-03-10-012B Date: February 01, 2008 INFORMATION Subject: Pitting and Brake Dust on Chrome wheels Models: 2008 and Prior GM Passenger Cars and Trucks (including Saturn) 2008 and Prior HUMMER H2, H3 2005-2008 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 04-03-10-012A (Section 03 - Suspension). Analysis of Returned Wheels Chrome wheels returned under the New Vehicle Limited Warranty for pitting concerns have recently been evaluated. This condition is usually most severe in the vent (or window) area of the front wheels. This "pitting" may actually be brake dust that has been allowed to accumulate on the wheel. The longer this accumulation builds up, the more difficult it is to remove. Cleaning the Wheels In all cases, the returned wheels could be cleaned to their original condition using GM Vehicle Care Cleaner Wax, P/N 12377966 (in Canada, P/N 10952905). When using this product, you should confine your treatment to the areas of the wheel that show evidence of the brake dust build-up. This product is only for use on chromed steel or chromed aluminum wheels. Parts Information Warranty Information Wheel replacement for this condition is NOT applicable under the terms of the New Vehicle Limited Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 99-03-10-102 > Jun > 99 > Warranty - OE Chrome Plated Aluminum Wheel ID Wheels: All Technical Service Bulletins Warranty - OE Chrome Plated Aluminum Wheel ID File In Section: 03 - Suspension Bulletin No.: 99-03-10-102 Date: June, 1999 INFORMATION Subject: Original Equipment Chrome Plated Aluminum Wheel Identification Models: 1999 and Prior Passenger Cars and Light Duty Trucks Chrome plated aluminum wheels have been returned to the Warranty Parts Center that are not the original equipment (OE) components. Original equipment chrome plated aluminum wheels can be identified by either a balance weight clip retention groove (1) or a step (2) that is machined around both of the wheel's rim flanges. The rim flanges (3) of painted original equipment aluminum wheels do not have a groove or a step. Chrome plated aluminum wheels that do not have the wheel rim flange groove or step are aftermarket chrome plated components and are NOT warrantable. Any aftermarket chrome wheels received by the Warranty Parts Center will be charged back to the dealership. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 72-05-05 > Aug > 97 > Warranty - Guidelines for Using E0420 Wheel Replace Wheels: All Technical Service Bulletins Warranty - Guidelines for Using E0420 Wheel Replace File In Section: Warranty Administration Bulletin No.: 72-05-05 Date: August, 1997 WARRANTY ADMINISTRATION Subject: Guidelines for Using EO42O Wheel Replace Models: 1989-98 Passenger Cars and Light Duty Trucks The purpose of this bulletin is to provide service personnel with guidelines for using the above subject labor operation. Effective with repair orders dated on or after September 1, 1997, dealers are to be guided by the following: ^ Aluminum Wheels (including chrome plated) with Porosity - Wheels that exhibit porosity should be repaired as described in the vehicle service manual. Wheels should not be replaced without wholesale approval. ^ Aluminum Wheels (except chrome plated) with a "Finish Defect" - Wheels that exhibit a defect in the finish, (i.e., discoloration or surface degradation) should be refinished as described in the Corporate Service Bulletin Number 53-17-03A released in May, 1996. ^ Chrome Wheels - Wheels that are chromed and found to have a finish defect can only be replaced. ^ Aluminum and chrome wheels replaced under warranty will be subject to random part review and inspection. Those wheels inspected and found not to be defective and/or should have been repaired, will be subject to charge back. Wheels damaged by normal wear, road hazards, car wash brushes, or other physical or chemical damage are not eligible for warranty coverage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing Technical Service Bulletin # 531703A Date: 960501 Aluminum Wheels - Refinishing File In Section: 10 - Body Bulletin No.: 53-17-03A Date: May, 1996 INFORMATION Subject: Aluminum Wheel Refinishing Models: 1991-96 Passenger Cars and Trucks This bulletin is being revised to delete the 1990 model year and add the 1996 model year. Please discard Corporate Bulletin Number 53-17-03 (Section 10 - Body). This bulletin supersedes and cancels all previous service bulletins concerning the refinishing of aluminum wheels. The purpose of this service bulletin is to assist dealerships in repairing the discoloration or surface degradation that has occurred on styled aluminum wheels. This bulletin provides NEW PROCEDURES AND SPECIFIC MATERIALS for the refinishing of painted aluminum wheels or aluminum wheels with discoloration or surface degradation. Important: THE RE-MACHINING OF ALUMINUM WHEELS IS NOT RECOMMENDED. THE RE-CLEAR COATING OF ALUMINUM WHEELS IS NO LONGER RECOMMENDED DUE TO CONCERNS OF REPAIR DURABILITY The new procedure requires the wheel surface be plastic media blasted to remove old paint or clear coat. CHEMICAL STRIPPERS ARE NOT RECOMMENDED. Material Required System 1: DuPont Products 3939-S Cleaning Solvent 615/616 Etching Primer URO 5000 Primer Surfacer IMRON 6000 Basecoat 3440-S IMRON Clear System 2: PPG Products DX533 Aluminum Cleaner DX503 Aluminum Conditioner DP Epoxy Primer Deltron Basecoat (DBC) Concept 2001 Clear Acrylic Urethane System 3: Spies Hecker Permahyd Silicone Remover 7090 Permahyd 1:1 Primer 4070 Permahyd 2:1 Surfacer 5080 Permahyd Base Coat Series 280/285 Permahyd H.S. Clearcoat 8060 Color Selection If the wheels being painted were previously clearcoated aluminum, we would recommend using Corsican SILVER WAEQ9283 for a fine "aluminum-like" look or Sparkle SILVER WA9967 for a very bright look. As an option to the customer, you may also use body color. For color Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing > Page 7916 selection and verification, refer to your paint manufacturer's color book. On wheels that were previous clearcoated aluminum it is recommended that all four wheels and their center caps be refinished to maintain color uniformity. Important: THE PRODUCTS LISTED MUST BE USED AS A SYSTEM. DO NOT MIX OTHER MANUFACTURERS' PRODUCT LINES WITH THE REQUIRED MATERIALS. PRODUCTS LISTED IN THIS BULLETIN HAVE SHOWN THE REQUIRED REPAIR DURABILITY, AND CURRENTLY ARE THE ONLY PAINT SYSTEMS THAT MEET GM SPECIFICATION 4350M-A336. Procedures 1. Remove wheels from vehicle. Tires may remain mounted on wheels. 2. Remove balance weights and mark their location on tire. 3. Wipe excess grease, etc. from wheels with wax and grease remover. 4. Have wheels plastic media blasted to remove clearcoat. FOR FURTHER INFORMATION ON MEDIA BLASTING IN YOUR AREA, CALL US TECHNOLOGIES INC., CONTACT DAVE ROSENBURG AT 1-800-634-9185. Caution: IT IS MANDATORY THAT ADEQUATE RESPIRATORY PROTECTION BE WORN. EXAMPLES OF SUCH PROTECTION ARE: AIR LINE RESPIRATORS WITH FULL HOOD OR HALF MASK. IF NOT AVAILABLE, USE A VAPOR/PARTICULATE RESPIRATOR THAT RESPIRATOR MANUFACTURER RECOMMENDS AS EFFECTIVE FOR ISOCYANATE VAPOR AND MISTS (UNLESS LOCAL REGULATIONS PREVAIL). 5. Painting Process a. Refer to Attachments 1-3 for each System's individual formula and process. b. After following the specific System's individual formula and process, follow these steps: 6. Unmask wheels. 7. Clean all wheel mounting surface of any corrosion, overspray, or dirt. 8. Install new coated balance weights, at marked locations. 9. Replace wheels on vehicle. 10. USE A TORQUE STICK ON AN IMPACT WRENCH, OR A TORQUE WRENCH TO CONSISTENTLY AND UNIFORMLY FASTEN THE WHEEL TO THE SPECIFIED TORQUE FOR THE VEHICLE. THE STAR PATTERN MUST BE FOLLOWED. Important: TORQUE STICKS MUST BE USED ANY TIME AN IMPACT WRENCH IS USED TO TIGHTEN WHEEL NUTS. Warranty Information For vehicles repaired under warranty, use as shown. Attachment 1 - DuPont Products Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing > Page 7917 Painting Process System: Dupont Products Paint Color Information: Corsican Silver WA EQ9283 Dupont # C9143, Sparkle Silver WA9967 Dupont # C9339 1. Wipe wheel with cleaning solvent: 3939-S, 3949-S or 3900-S. 2. Mask off tires. Important: 3. Mask off all wheel mounting surfaces and wheel mount surfaces. 4. Apply two coats of 615/616-S etching primer to wheel allowing 10 minutes flash between coats. Allow to dry for 30 minutes before applying primer coat. 5. Apply URO 5000 primer 1220/193-S + accelerator 389-S using two coats at 65-70 PSI at the gun. Allow 12-15 minutes between coats. Force bake 30 minutes at 140°F (60°C). 6. Scuff sand using green Scotch-Brite pad. 7. Solvent wipe before top coating. 8. Apply IMRON 6000 base coat to wheel. 2-3 coats to hiding at 60-70 PSI allowing to flash between coats. Base coat needs to dry 20-30 minutes before clearcoat is applied. 9. Apply 3440-S clearcoat to wheel using two coats at 60-70 PSI. Flash 10-15 minutes between coats. 389-S can be used in basecoat and clearcoat to give faster set up times. 10. Allow overnight dry before reassemble. Can be baked for 30 minutes at 140°F (60°C). Attachment 2 - PPG Products Painting Process: PPG System Paint Color Information: Corsican Silver WAEQ9283; PPG # DBC-3531, Sparkle Silver WA9967; PPG # 35367 1. Wash entire wheel with aluminum cleaner DX533, mix 1:3 with water. Allow to react 2-3 minutes and rinse thoroughly. 2. Wash entire wheel with aluminum conditioner DX5O3 straight from the container. Allow to react 2-3 minutes until pale gold or tan color develops. Rinse thoroughly and dry. 3. Mask off tires. Important: 4. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 5. Apply 1-2 coats of DP Primer and allow to flash for 15-20 minutes. 6. Apply 2-3 coats of Deltron Basecoat (DBC) and allow to flash 20 minutes after the final coat. 7. Apply two (2) wet coats of Concept 2001 Acrylic urethane. 8. Flash 20 minutes and bake 140°F (60°C) for 30 minutes. For more information contact your PPG Jobber. Attachment 3 - Spies Hecker Painting Process: Spies Hecker System Paint Color Information: Corsican Silver AWEQ9283; SH-72913, Sparkle Silver WA9967; SH-71912 1. Clean with Permahyd Silicone Remover 7090. 2. Mask off tires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheels > Component Information > Technical Service Bulletins > All Other Service Bulletins for Wheels: > 531703A > May > 96 > Aluminum Wheels Refinishing > Page 7918 Important: 3. Mask off all wheel nut mounting surfaces and wheel mounting surfaces. 4. Apply 1-1/2 coats of Permahyd 1:1 Primer 4070. Mix 1:1 with Permahyd Hardener 3070 as per TDS. 5. Allow to flash for 30 minutes. 6. Apply two (2) coats of Permahyd 2:1 Surfacer 5080. Mix 2:1 with Permahyd Hardener 3071 as per TDS. 7. Bake for 60 minutes at 140°F (60°C) or allow to flash for 3 hours at 68°F (20°C). 8. Apply Permahyd Base Coat Series 280/285 as per TDS. 9. Allow to flash 10 to 15 minutes. 10. Apply 1 to 2 coats of Permacron High Solid Clear Coat 8060 as per TDS. 11. Allow to flash 10 minutes. Then bake at 140°F (60°C) for 40 minutes. For more information, contact your SPIES HECKER Jobber. We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheel Bearing > Component Information > Adjustments Wheel Bearing: Adjustments FRONT WHEEL BEARINGS ADJUSTMENT Fig. 2 Front Wheel Bearing Adjustment 1. While rotating wheel forward, torque spindle nut to 12 ft. lbs., Fig. 2. 2. Back off nut until just loose then hand tighten nut and back it off again until either hole in spindle lines up with hole in nut. Do not back off nut more than 1/2 flat. 3. Install new cotter pin. With wheel bearing properly adjusted, there will be .001-.005 inch end play. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheel Bearing > Component Information > Adjustments > Page 7922 Wheel Bearing: Service and Repair FRONT WHEEL BEARINGS Fig. 3 Hub & Wheel Bearing Replacement 1. Raise car and remove front wheels. 2. On models equipped with anti-lock brake systems, remove right and left wheel speed sensors as follows: a. Under vehicle hood, disconnect speed sensor electrical harness. b. Raise and support vehicle, then remove speed sensor harness bracket attaching bolt. c. Remove speed sensor to steering knuckle attaching bolt, then remove speed sensor and bracket assembly and position aside. d. Reverse procedure to install. Install wheel speed sensors by hand. Do not hammer sensors into position, as damage may result. 3. On all models, remove bolts holding brake caliper to its mounting and insert a fabricated block (11/16 x 1 1/16 x 2 inches in length) between brake pads as caliper is being removed. Once removed, caliper can be wired or secured in some manner away from disc. 4. Remove spindle nut and hub and disc assembly. Grease retainer and inner wheel bearing can now be removed, Fig. 3. 5. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > Customer Interest for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels - Plastic Wheel Nut Covers Loose/Missing Wheel Fastener: Customer Interest Wheels - Plastic Wheel Nut Covers Loose/Missing Bulletin No.: 01-03-10-009A Date: July 27, 2004 TECHNICAL Subject: Plastic Wheel Nut Covers Missing and/or Loose (Replace Missing Covers and Add Sealant to All Covers) Models: 2005 and All Prior Passenger Cars (Except All Cadillac Models and Pontiac GTO) with Plastic Wheel Nut Covers Supercede: This bulletin is being revised to add additional models years. Please discard Corporate Bulletin Number 01-03-10-009. Condition Some customers may comment that the plastic wheel nut covers are missing and/or loose. Correction Important: ^ DO NOT USE a silicone-based adhesive. ^ Do not apply the *permatex(R) around the threads in a circular pattern. ^ Apply a single bead across the threads approximately 10 mm (0.4 in) in length, 5 mm (0.2 in) in height and 5 mm (0.2 in) in width. Replace any missing plastic wheel nut covers with the appropriate covers and apply Permatex(R) # 2 Form A Gasket Sealant(R) to the threads of all the plastic wheel nut covers. Tighten finger tight plus a 1/4 turn with a hand wrench. *We believe this source and their products to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any other such items which may be available from other sources. Permatex(R) # 2 Form A Gasket Sealant(R) part numbers (available at your local parts supplier) ^ P/N 80009 (2A/2AR) - 44 ml (1.5 oz) tube boxed ^ P/N 80015 (2AR) - 44 ml (1.5 oz) tube carded ^ P/N 80010 (2B/2BR) - 89 ml (3 oz) tube boxed ^ P/N 80016 (2BR) - 89 ml (3 oz) tube carded ^ P/N 80011 (2C) - 325 ml (11 oz) tube boxed Warranty Information For vehicles repaired under warranty, use the table. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > Customer Interest for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels - Plastic Wheel Nut Covers Loose/Missing > Page 7931 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels Plastic Wheel Nut Covers Loose/Missing Wheel Fastener: All Technical Service Bulletins Wheels - Plastic Wheel Nut Covers Loose/Missing Bulletin No.: 01-03-10-009A Date: July 27, 2004 TECHNICAL Subject: Plastic Wheel Nut Covers Missing and/or Loose (Replace Missing Covers and Add Sealant to All Covers) Models: 2005 and All Prior Passenger Cars (Except All Cadillac Models and Pontiac GTO) with Plastic Wheel Nut Covers Supercede: This bulletin is being revised to add additional models years. Please discard Corporate Bulletin Number 01-03-10-009. Condition Some customers may comment that the plastic wheel nut covers are missing and/or loose. Correction Important: ^ DO NOT USE a silicone-based adhesive. ^ Do not apply the *permatex(R) around the threads in a circular pattern. ^ Apply a single bead across the threads approximately 10 mm (0.4 in) in length, 5 mm (0.2 in) in height and 5 mm (0.2 in) in width. Replace any missing plastic wheel nut covers with the appropriate covers and apply Permatex(R) # 2 Form A Gasket Sealant(R) to the threads of all the plastic wheel nut covers. Tighten finger tight plus a 1/4 turn with a hand wrench. *We believe this source and their products to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any other such items which may be available from other sources. Permatex(R) # 2 Form A Gasket Sealant(R) part numbers (available at your local parts supplier) ^ P/N 80009 (2A/2AR) - 44 ml (1.5 oz) tube boxed ^ P/N 80015 (2AR) - 44 ml (1.5 oz) tube carded ^ P/N 80010 (2B/2BR) - 89 ml (3 oz) tube boxed ^ P/N 80016 (2BR) - 89 ml (3 oz) tube carded ^ P/N 80011 (2C) - 325 ml (11 oz) tube boxed Warranty Information For vehicles repaired under warranty, use the table. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Wheel Fastener: > 01-03-10-009A > Jul > 04 > Wheels Plastic Wheel Nut Covers Loose/Missing > Page 7937 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Steering and Suspension > Wheels and Tires > Wheel Fastener > Component Information > Technical Service Bulletins > Page 7938 Wheel Fastener: Specifications Wheel Nuts .......................................................................................................................................... ................................................ 140 Nm (100 ft lb) CAUTION: If penetrating oil gets on the vertical surfaces between the wheel and the rotor or brake drum. it could cause the wheel to work loose as the vehicle is driven, resulting in a loss of control and an injury accident. Never use heat to loosen a tight wheel. It can shorten the life of the wheel, bolts or spindle and bearings. Wheel nuts must be tightened in sequence and to the proper torque to avoid bending the wheel or rotor. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Conditioning Switch > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Door, HVAC > Air Door Actuator / Motor, HVAC > Component Information > Locations > Air Mix Motor Rear View Of Center Instrument Panel (With C67 Or C68) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Door, HVAC > Air Door Actuator / Motor, HVAC > Component Information > Locations > Air Mix Motor > Page 7948 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Door, HVAC > Air Door Actuator / Motor, HVAC > Component Information > Locations > Air Mix Motor > Page 7949 Rear View Of Center Instrument Panel (With C67 Or C68) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Door, HVAC > Air Door Actuator / Motor, HVAC > Component Information > Locations > Air Mix Motor > Page 7950 Air Door Actuator / Motor: Locations Mode Valve Actuator Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Door, HVAC > Air Door Actuator / Motor, HVAC > Component Information > Locations > Air Mix Motor > Page 7951 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Door, HVAC > Air Door Actuator / Motor, HVAC > Component Information > Locations > Air Mix Motor > Page 7952 Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Air Door, HVAC > Air Door Actuator / Motor, HVAC > Component Information > Locations > Page 7953 Temperature Valve Actuator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Ambient Temperature Sensor / Switch HVAC > Component Information > Locations > Inside Air Temperature Sensor Ambient Temperature Sensor / Switch HVAC: Locations Inside Air Temperature Sensor Instrument Panel Carrier, above Glove Box. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Ambient Temperature Sensor / Switch HVAC > Component Information > Locations > Inside Air Temperature Sensor > Page 7958 Ambient Temperature Sensor / Switch HVAC: Locations Outside Air Temperature Sensor Attached to Hood Latch Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates Blower Motor: Customer Interest A/C - Odor at Start up in Humid Climates File In Section: 1 - HVAC Bulletin No.: 53-12-12A Date: December, 1996 Subject: Air Conditioning Odor at Start Up in Humid Climates (Disinfect Evaporator Core, Install Delayed Blower Control Package) Models: 1993-96 Passenger Cars (Except GEO) 1993-96 Light Duty Models (Except Tracker) This bulletin is being revised to update the wiring diagrams, add the Corvette (with RPO C60) and delete medium/heavy duty trucks. Please discard Corporate Bulletin Number 53-12-12 (Section 1 HVAC). Condition Some owners may comment on odors emitted from the air conditioning system, primarily at start up in hot, humid climates. Cause This odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. Correction To remove odors of this type, it is necessary to eliminate the microbial growth and prevent its recurrence. To accomplish this, these two procedures must be completed. ^ Deodorize the evaporator core using Deodorizing Aerosol Kit, P/N 12377951 (AC Delco 15-102). ^ Install the new A/C Delayed Blower Control Package, P/N 12370470, (AC Delco 15-8632). The blower control package will enable the blower to run at high speed for five (5) minutes. It will do so approximately fifty (50) minutes after the ignition has been turned off if the compressor had been engaged for four (4) or more minutes prior to shutting off engine. By doing so, the evaporator case and core are dried out, reducing the chances of a recurring A/C odor. Procedure 1. Visually inspect the air conditioning evaporator drain hose for obstructions or working condition. 2. Apply deodorizing aerosol as described in the instructions supplied with the kit. Once the deodorizer has been applied, some of the mixture may overflow from the drain hose. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7967 3. The chart identifies specific instructions for each vehicle. This chart will identify the proper deodorizing procedure, template and wiring diagram. Deodorizing the evaporator case can easily be done by removing the blower motor resistor and tape off opening. The nozzle can now be inserted through a pierced hole in the tape to deodorize the evaporator case. For some of the vehicles specified below, a drilling procedure is identified in the deodorizing instructions. This type of alternative procedure and others can be done by using the referenced templates in the chart. 4. Complete detailed installation instructions are supplied with the blower control package. Important: A. 1996 ONLY (Use blower resistor location for drilling procedure) B. 1994-1996 ONLY Refer to appropriate Service Manual for enabling afterblow feature through on-board diagnostics. Parts Information Parts are currently available from GMSPO. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7968 For vehicles repaired under warranty, use as shown. Figure 1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7969 Figure 2 Figure 3 Figure 4 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7970 Figure 5 Figure 6 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7971 Figure 7 Figure 8 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7972 Figure 9 Figure 10 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7973 Figure 11 Figure 12 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7974 Figure 13 Figure 14 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7975 Figure 15 Figure 16 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7976 Figure 17 Figure 18 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7977 Figure 19 Figure 20 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7978 Figure 21 Figure 22 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7979 Figure 23 Figure 24 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7980 Figure 25 Figure 26 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Customer Interest for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7981 Figure 27 Figure 28 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates Blower Motor: All Technical Service Bulletins A/C - Odor at Start up in Humid Climates File In Section: 1 - HVAC Bulletin No.: 53-12-12A Date: December, 1996 Subject: Air Conditioning Odor at Start Up in Humid Climates (Disinfect Evaporator Core, Install Delayed Blower Control Package) Models: 1993-96 Passenger Cars (Except GEO) 1993-96 Light Duty Models (Except Tracker) This bulletin is being revised to update the wiring diagrams, add the Corvette (with RPO C60) and delete medium/heavy duty trucks. Please discard Corporate Bulletin Number 53-12-12 (Section 1 HVAC). Condition Some owners may comment on odors emitted from the air conditioning system, primarily at start up in hot, humid climates. Cause This odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. Correction To remove odors of this type, it is necessary to eliminate the microbial growth and prevent its recurrence. To accomplish this, these two procedures must be completed. ^ Deodorize the evaporator core using Deodorizing Aerosol Kit, P/N 12377951 (AC Delco 15-102). ^ Install the new A/C Delayed Blower Control Package, P/N 12370470, (AC Delco 15-8632). The blower control package will enable the blower to run at high speed for five (5) minutes. It will do so approximately fifty (50) minutes after the ignition has been turned off if the compressor had been engaged for four (4) or more minutes prior to shutting off engine. By doing so, the evaporator case and core are dried out, reducing the chances of a recurring A/C odor. Procedure 1. Visually inspect the air conditioning evaporator drain hose for obstructions or working condition. 2. Apply deodorizing aerosol as described in the instructions supplied with the kit. Once the deodorizer has been applied, some of the mixture may overflow from the drain hose. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7987 3. The chart identifies specific instructions for each vehicle. This chart will identify the proper deodorizing procedure, template and wiring diagram. Deodorizing the evaporator case can easily be done by removing the blower motor resistor and tape off opening. The nozzle can now be inserted through a pierced hole in the tape to deodorize the evaporator case. For some of the vehicles specified below, a drilling procedure is identified in the deodorizing instructions. This type of alternative procedure and others can be done by using the referenced templates in the chart. 4. Complete detailed installation instructions are supplied with the blower control package. Important: A. 1996 ONLY (Use blower resistor location for drilling procedure) B. 1994-1996 ONLY Refer to appropriate Service Manual for enabling afterblow feature through on-board diagnostics. Parts Information Parts are currently available from GMSPO. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7988 For vehicles repaired under warranty, use as shown. Figure 1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7989 Figure 2 Figure 3 Figure 4 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7990 Figure 5 Figure 6 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7991 Figure 7 Figure 8 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7992 Figure 9 Figure 10 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7993 Figure 11 Figure 12 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7994 Figure 13 Figure 14 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7995 Figure 15 Figure 16 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7996 Figure 17 Figure 18 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7997 Figure 19 Figure 20 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7998 Figure 21 Figure 22 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 7999 Figure 23 Figure 24 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8000 Figure 25 Figure 26 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Blower Motor: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8001 Figure 27 Figure 28 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Page 8002 Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor > Component Information > Technical Service Bulletins > Page 8003 Blower Motor: Service and Repair 1. Disconnect battery ground cable. 2. Remove righthand instrument panel sound insulator attaching screws, then pull panel rearward disengaging attaching studs. 3. Disconnect blower assembly electrical connector. 4. Remove righthand hinge pillar trim finish panel. 5. Remove secondary ECM bracket attaching screw, then position secondary ECM and bracket aside. 6. Support blower motor assembly, then remove blower motor assembly attaching screws. 7. Remove blower motor assembly. 8. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor Relay > Component Information > Locations Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor Relay > Component Information > Locations > Page 8007 LO Blower Relay, Rear Defog Relay And HI Blower Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor Resistor > Component Information > Locations Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor Resistor > Component Information > Locations > Page 8011 Blower Resistor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor Switch > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Blower Motor Switch > Component Information > Locations > Page 8015 Heater And A/C Blower Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Cabin Air Filter > Component Information > Locations Cabin Air Filter: Locations This vehicle does not contain a factory installed cabin air filter. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Specifications Compressor Clutch: Specifications Clutch Plate & Rotor Clearance ............................................................................................................................................... 0.50-0.76mm (0.020-0.030) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Specifications > Page 8023 Compressor Clutch: Locations RH side of Engine, part of A/C Compressor Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly Compressor Clutch: Service and Repair Clutch Plate and Hub Assembly Remove or Disconnect Clutch Plate And Hub Assembly Removal 1. Clamp the holding fixture J 33026 in a vise and attach compressor to holding fixture with thumb screws J 33026-1. 2. With center screw forcing tip in place to thrust against the end of the shaft, thread the Clutch Plate and Hub Assembly Installer-Remover J 33013-B into the hub. Hold the body of the remover with a wrench and turn the center screw into the remover body to remove the clutch plate and hub assembly (Fig. 3). NOTICE: Do not drive or pound on the clutch hub or shaft. Internal damage to compressor may result. The forcing tip on J 33013-B remover-installer center screw must be flat or the end of the shaft/axial plate assembly will be damaged. 3. Remove the shaft key and retain for reassembly. Install or Connect Shaft Key, Clutch Plate/Hub Installation 1. Install the shaft key into the hub key groove. Allow the key to project approximately 3.2mm (1/8") out of the keyway. The shaft key is curved slightly to provide an interference fit in the hub key groove. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8026 2. Be sure the frictional surface of the clutch plate and the clutch rotor are clean before installing the clutch plate and hub assembly. 3. Align the shaft key with the shaft keyway and place the clutch plate and the hub assembly onto the compressor shaft. Installing Clutch Plate & Hub Assembly 4. Remove the forcing tip on J 33013-B clutch plate and hub assembly installer-remover center screw and reverse the body direction on the center screw, as shown in the illustration. 5. Install the clutch plate and hub installer-remover J 33013-B with bearing. The body of the J 33013-B installer-remover should be backed off sufficiently to allow the center screw to be threaded onto the end of the compressor shaft. 6. Hold the center screw with a wrench. Tighten the hex portion of the installer-remover J 33013-B body to press the hub onto the shaft. Tighten the body several turns, remove the installer and check to see that the shaft key is still in place in the keyway before installing the clutch plate and hub assembly to its final position. The air gap between frictional surfaces of the clutch plate and clutch rotor should be 0.50-0.76mm (0.020-0.030"). NOTICE: If the center screw is threaded fully onto the end of the compressor shaft. or if the body of the installer is held and the center screw is rotated, the key will wedge and will break the clutch hub. 7. Remove installer J 33013-B, check for proper positioning of the shaft key (even or slightly above the clutch hub). 8. Spin the pulley rotor by hand to see that the rotor is not rubbing the clutch drive plate. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8027 Compressor Clutch: Service and Repair Clutch Rotor and/or Bearing Remove or Disconnect 1. Remove the clutch plate and hub assembly as described previously. Installing - Removing Pulley Rotor & Bearing Assembly Retaining Ring 2. Remove rotor and bearing assembly retaining ring, using snap ring pliers J 6083. Installing Pulley Rotor/Bearing Puller Guide Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8028 Removing Pulley Rotor And Bearing Assembly 3. Install pulley rotor and bearing puller guide J 33023-A to the front head and install J 33020 pulley rotor and bearing puller down into the inner circle of slots in the rotor. Turn the J 33020 puller clockwise in the slots in the rotor. 4. Hold the J 33020 puller in place and tighten the puller screw against the puller guide to remove the pulley rotor and bearing assembly. 5. To prevent damage to the pulley rotor during bearing removal the rotor hub must be properly supported. Pulley Rotor Bearing Removal Remove the forcing screw from J 33020 puller and, with the puller tangs still engaged in the rotor slots, invert the assembly onto a solid flat surface or blocks as shown in the illustration. 6. Drive the bearing out of the rotor hub with rotor bearing remover J 9398-A and J 29886 universal handle. NOTICE: It is not necessary to remove the staking in front of the bearing to remove the bearing, however, it will be necessary to file away the old stake metal for proper clearance for the new bearing to be installed into the rotor bore or the bearing may be damaged. Install or Connect Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8029 Installing Pulley Rotor Bearing 1. lace the pulley rotor on the J 21352-A support block to fully support the rotor hub during bearing installation. NOTICE: DO NOT support the rotor by resting the pulley rim on a flat surface during the bearing installation or the rotor face will be bent. 2. Align the new bearing squarely with the hub bore and using puller and bearing installer J 9481-A with universal handle J 29886, drive the bearing fully into the hub. The installer will apply force to the outer race of the bearing, if used as shown. Staking Bearing In Rotor Hub Bore 3. Place bearing staking guide J 33019-1 and bearing staking pin J 33019-2 in the hub bore as shown in the illustration. Shift the rotor and bearing assembly on the J 21352-A support block to give full support of the hub under the staking pin location. A heavy-duty rubber band may be used to hold the stake pin in the guide, and the stake pin should be properly positioned in the guide after each impact on the pin. 4. Using care to prevent personal injury, strike the staking pin with a hammer until a metal stake, similar to the original, is formed down to but not touching the bearing. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8030 Bearing Staked In Place Noisy bearing operation and reduced bearing life may result if outer bearing race is deformed while staking, The stake metal should not contact the outer race of the bearing. Stake three places 120 degrees apart as shown in the illustration. Installing Pulley Rotor And Bearing Assembly 5. With the compressor mounted to the J 33026 holding fixture, position the rotor and bearing assembly on the front head. 6. Position the J 33017 pulley, rotor and bearing installer and J 33023-A puller pilot directly over the inner race of the bearing. 7. Position puller crossbar J 8433-1 on the puller pilot J 33023-A and assemble the two J 330262 through bolts and washers through the puller bar slots and thread them into the J 33026 holding fixture. The thread of the through bolts should engage the full thickness of the holding fixture. 8. Tighten the center screw in the J 8433-1 puller crossbar to force the pulley rotor and bearing assembly onto the compressor front head. Should the J 33017 pulley rotor and bearing installer slip off direct in-line contact with the inner race of the bearing, loosen the J 8433-1 center forcing screw and realign the installer and pilot so that the J 33017 installer will properly clear the front head. 9. Install rotor and bearing assembly retainer ring, using snap ring pliers J 6083. 10. Reinstall clutch plate and hub assembly as described previously. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8031 Compressor Clutch: Service and Repair Clutch Coil Remove or Disconnect 1. Perform Steps through 4 of "Clutch Rotor and/or Bearings" removal procedure. Mark clutch coil terminal location on compressor front head. Clutch Coil Assembly Removal 2. Install J 33023-A puller pilot on front head of compressor. Also install J 8433-1 puller crossbar with J 33025 puller legs as shown in the illustration. 3. Tighten J 8433-3 forcing screw against the puller pilot to remove the clutch coil. 1. Place the clutch coil assembly on the front head with the terminals positioned at the "marked" location. 2. Place the J 33024 clutch coil installer over the internal opening of the clutch coil housing and align installer with the compressor front head. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8032 Installing Clutch Coil Assembly 3. Center the J 8433-1 puller crossbar in the counter- sunk center hole of the J 33024 clutch coil installer. Install the J 3302-2 through bolts and washers through the crossbar slots and thread them into the holding fixture J 33026 to full fixture thickness. 4. Turn the center forcing screw of the J 8433-1 puller crossbar to force the clutch coil onto the front head. Be sure clutch coil and J 33024 installer stay "in-line" during installation. Staking Clutch Coil To Front Head 5. When coil is fully seated on the front head, use a 1/8" diameter drift punch and stake the front head at three places 120 degrees apart, to ensure clutch coil remains in position. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch > Component Information > Service and Repair > Clutch Plate and Hub Assembly > Page 8033 Details Of Stakes In Front Head For Clutch Coil ^ Stake size should be only one-half the area of the punch tip and be only approximately 0.28-0.35mm (0.010-0.015") deep. 6. Install rotor and bearing assembly and the clutch plate and hub assembly as described previously. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Bearing > Component Information > Service and Repair Compressor Clutch Bearing: Service and Repair Remove or Disconnect 1. Remove the clutch plate and hub assembly as described previously. Installing - Removing Pulley Rotor & Bearing Assembly Retaining Ring 2. Remove rotor and bearing assembly retaining ring, using snap ring pliers J 6083. Installing Pulley Rotor/Bearing Puller Guide Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Bearing > Component Information > Service and Repair > Page 8037 Removing Pulley Rotor And Bearing Assembly 3. Install pulley rotor and bearing puller guide J 33023-A to the front head and install J 33020 pulley rotor and bearing puller down into the inner circle of slots in the rotor. Turn the J 33020 puller clockwise in the slots in the rotor. 4. Hold the J 33020 puller in place and tighten the puller screw against the puller guide to remove the pulley rotor and bearing assembly. 5. To prevent damage to the pulley rotor during bearing removal the rotor hub must be properly supported. Pulley Rotor Bearing Removal Remove the forcing screw from J 33020 puller and, with the puller tangs still engaged in the rotor slots, invert the assembly onto a solid flat surface or blocks as shown in the illustration. 6. Drive the bearing out of the rotor hub with rotor bearing remover J 9398-A and J 29886 universal handle. NOTICE: It is not necessary to remove the staking in front of the bearing to remove the bearing, however, it will be necessary to file away the old stake metal for proper clearance for the new bearing to be installed into the rotor bore or the bearing may be damaged. Install or Connect Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Bearing > Component Information > Service and Repair > Page 8038 Installing Pulley Rotor Bearing 1. lace the pulley rotor on the J 21352-A support block to fully support the rotor hub during bearing installation. NOTICE: DO NOT support the rotor by resting the pulley rim on a flat surface during the bearing installation or the rotor face will be bent. 2. Align the new bearing squarely with the hub bore and using puller and bearing installer J 9481-A with universal handle J 29886, drive the bearing fully into the hub. The installer will apply force to the outer race of the bearing, if used as shown. Staking Bearing In Rotor Hub Bore 3. Place bearing staking guide J 33019-1 and bearing staking pin J 33019-2 in the hub bore as shown in the illustration. Shift the rotor and bearing assembly on the J 21352-A support block to give full support of the hub under the staking pin location. A heavy-duty rubber band may be used to hold the stake pin in the guide, and the stake pin should be properly positioned in the guide after each impact on the pin. 4. Using care to prevent personal injury, strike the staking pin with a hammer until a metal stake, similar to the original, is formed down to but not touching the bearing. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Bearing > Component Information > Service and Repair > Page 8039 Bearing Staked In Place Noisy bearing operation and reduced bearing life may result if outer bearing race is deformed while staking, The stake metal should not contact the outer race of the bearing. Stake three places 120 degrees apart as shown in the illustration. Installing Pulley Rotor And Bearing Assembly 5. With the compressor mounted to the J 33026 holding fixture, position the rotor and bearing assembly on the front head. 6. Position the J 33017 pulley, rotor and bearing installer and J 33023-A puller pilot directly over the inner race of the bearing. 7. Position puller crossbar J 8433-1 on the puller pilot J 33023-A and assemble the two J 330262 through bolts and washers through the puller bar slots and thread them into the J 33026 holding fixture. The thread of the through bolts should engage the full thickness of the holding fixture. 8. Tighten the center screw in the J 8433-1 puller crossbar to force the pulley rotor and bearing assembly onto the compressor front head. Should the J 33017 pulley rotor and bearing installer slip off direct in-line contact with the inner race of the bearing, loosen the J 8433-1 center forcing screw and realign the installer and pilot so that the J 33017 installer will properly clear the front head. 9. Install rotor and bearing assembly retainer ring, using snap ring pliers J 6083. 10. Reinstall clutch plate and hub assembly as described previously. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Coil > Component Information > Service and Repair Compressor Clutch Coil: Service and Repair Remove or Disconnect 1. Perform Steps through 4 of "Clutch Rotor and/or Bearings" removal procedure. Mark clutch coil terminal location on compressor front head. Clutch Coil Assembly Removal 2. Install J 33023-A puller pilot on front head of compressor. Also install J 8433-1 puller crossbar with J 33025 puller legs as shown in the illustration. 3. Tighten J 8433-3 forcing screw against the puller pilot to remove the clutch coil. 1. Place the clutch coil assembly on the front head with the terminals positioned at the "marked" location. 2. Place the J 33024 clutch coil installer over the internal opening of the clutch coil housing and align installer with the compressor front head. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Coil > Component Information > Service and Repair > Page 8043 Installing Clutch Coil Assembly 3. Center the J 8433-1 puller crossbar in the counter- sunk center hole of the J 33024 clutch coil installer. Install the J 3302-2 through bolts and washers through the crossbar slots and thread them into the holding fixture J 33026 to full fixture thickness. 4. Turn the center forcing screw of the J 8433-1 puller crossbar to force the clutch coil onto the front head. Be sure clutch coil and J 33024 installer stay "in-line" during installation. Staking Clutch Coil To Front Head 5. When coil is fully seated on the front head, use a 1/8" diameter drift punch and stake the front head at three places 120 degrees apart, to ensure clutch coil remains in position. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Coil > Component Information > Service and Repair > Page 8044 Details Of Stakes In Front Head For Clutch Coil ^ Stake size should be only one-half the area of the punch tip and be only approximately 0.28-0.35mm (0.010-0.015") deep. 6. Install rotor and bearing assembly and the clutch plate and hub assembly as described previously. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Hub > Component Information > Specifications Compressor Clutch Hub: Specifications Clutch Plate & Rotor Clearance ............................................................................................................................................... 0.50-0.76mm (0.020-0.030) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Hub > Component Information > Specifications > Page 8048 Compressor Clutch Hub: Service and Repair Remove or Disconnect Clutch Plate And Hub Assembly Removal 1. Clamp the holding fixture J 33026 in a vise and attach compressor to holding fixture with thumb screws J 33026-1. 2. With center screw forcing tip in place to thrust against the end of the shaft, thread the Clutch Plate and Hub Assembly Installer-Remover J 33013-B into the hub. Hold the body of the remover with a wrench and turn the center screw into the remover body to remove the clutch plate and hub assembly (Fig. 3). NOTICE: Do not drive or pound on the clutch hub or shaft. Internal damage to compressor may result. The forcing tip on J 33013-B remover-installer center screw must be flat or the end of the shaft/axial plate assembly will be damaged. 3. Remove the shaft key and retain for reassembly. Install or Connect Shaft Key, Clutch Plate/Hub Installation 1. Install the shaft key into the hub key groove. Allow the key to project approximately 3.2mm (1/8") out of the keyway. The shaft key is curved slightly to provide an interference fit in the hub key groove. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Clutch Hub > Component Information > Specifications > Page 8049 2. Be sure the frictional surface of the clutch plate and the clutch rotor are clean before installing the clutch plate and hub assembly. 3. Align the shaft key with the shaft keyway and place the clutch plate and the hub assembly onto the compressor shaft. Installing Clutch Plate & Hub Assembly 4. Remove the forcing tip on J 33013-B clutch plate and hub assembly installer-remover center screw and reverse the body direction on the center screw, as shown in the illustration. 5. Install the clutch plate and hub installer-remover J 33013-B with bearing. The body of the J 33013-B installer-remover should be backed off sufficiently to allow the center screw to be threaded onto the end of the compressor shaft. 6. Hold the center screw with a wrench. Tighten the hex portion of the installer-remover J 33013-B body to press the hub onto the shaft. Tighten the body several turns, remove the installer and check to see that the shaft key is still in place in the keyway before installing the clutch plate and hub assembly to its final position. The air gap between frictional surfaces of the clutch plate and clutch rotor should be 0.50-0.76mm (0.020-0.030"). NOTICE: If the center screw is threaded fully onto the end of the compressor shaft. or if the body of the installer is held and the center screw is rotated, the key will wedge and will break the clutch hub. 7. Remove installer J 33013-B, check for proper positioning of the shaft key (even or slightly above the clutch hub). 8. Spin the pulley rotor by hand to see that the rotor is not rubbing the clutch drive plate. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Shaft Seal > Component Information > Technical Service Bulletins > A/C Compressor Seal Washer - Reference Chart Compressor Shaft Seal: Technical Service Bulletins A/C Compressor Seal Washer - Reference Chart File In Section: 1 - HVAC Bulletin No.: 63-12-15 Date: November, 1996 INFORMATION Subject: Reference Chart for A/C Compressor Seal Washers Models: 1997 and Prior Passenger Cars (Except Corvette and GEO) 1997 and Prior Light Duty Trucks (Except Tracker) GMSPO A/C compressors include a seal washer kit. These kits contain various color edge painted washer seals and inserts in which only two (2) washers and possibly one (1) insert are used. It has come to our attention that some packaging discrepancies were found and some of the seals cannot be properly identified for installation. These seals are very close in size and some of the seals were inadvertently edge painted the wrong color or not painted. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Shaft Seal > Component Information > Technical Service Bulletins > A/C Compressor Seal Washer - Reference Chart > Page 8054 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Shaft Seal > Component Information > Technical Service Bulletins > A/C Compressor Seal Washer - Reference Chart > Page 8055 The chart shown will help to properly identify the seals. Use the chart by placing the seal over the pictured seal to identity inside and outside diameters and thickness. Because these seals are very similar in size, specifications are also listed in the chart. Important: If seals are damaged upon installation, obtain new seal kit. Seals will be available separately at a later date. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Shaft Seal > Component Information > Technical Service Bulletins > Page 8056 Compressor Shaft Seal: Service and Repair Seal Leak Detection A shaft seal should not be changed because of small amounts of oil found on an adjacent surface but only after actual refrigerant leakage is found using an approved leak detector, J 39400 or equivalent. Remove or Disconnect 1. Recover the refrigerant using J 39500-GM. 2. Loosen and reposition compressor in mounting brackets, if necessary. 3. Remove clutch plate and hub assembly from compressor as described in minor repairs. Removing Or Installing Shaft Seal Retaining Ring 4. Remove the shaft seal retainer ring, using snap ring pliers J 5403. 5. Thoroughly clean inside of compressor neck area surrounding the shaft, the exposed portion of the seal, the retainer ring groove and the shaft itself. Any dirt or foreign material getting into compressor may cause damage. Removing Or Installing Shaft Seal 6. Fully engage the knurled tangs of Seal Remover-Installer J 23128-A into the recessed portion of the Seal by turning the handle clockwise. Remove Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Shaft Seal > Component Information > Technical Service Bulletins > Page 8057 the Seal from the compressor with a rotary-pulling motion. Discard the seal. The handle must be hand- tightened securely. Do not use a wrench or pliers. Removing And Installing Shaft Seal And O-Ring 7. Remove and discard the seal seat O-ring from the compressor neck using O-ring remover J 955301, illustration. 8. Recheck the shaft and inside of the compressor neck for dirt or foreign material and be sure these areas are perfectly clean before installing new parts. Clean ^ Thoroughly clean O-ring seal groove in front head. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor HVAC > Compressor Shaft Seal > Component Information > Technical Service Bulletins > Page 8058 Compressor Shaft Seal NOTICE: Seals should not be re-used. Always use a new specification service seal on rebuild. Be sure that the seal to be installed is not scratched or damaged in anyway. Make sure that the seal seat and seal are free of lint and dirt that could damage the seal surface or prevent sealing. Install or Connect 1. Dip the new seal seat O-ring in clean 525 viscosity refrigerant oil and assemble onto O-ring installer J 33011. 2. Insert the O-ring installer J 33011 into the compressor neck until the installer "bottoms". Lower the moveable slide of the O-ring installer to release the O-ring into the seal O-ring lower groove. (The compressor neck top groove is for the shaft seal retainer ring.) Rotate the installer to seat the O-ring and remove the installer. 3. Dip the new seal in clean 525 viscosity refrigerant oil and assemble seal to Seal Installer J 23128-A, by turning handle clockwise. The stamped steel case side of the lip seal must be engaged with knurled tangs of installer so that flared-out side of lip seal is facing and installed towards the compressor. Install seal protector J 34614, in the seal lip and place over the compressor shaft, and push the seal in place with a rotary motion or place the seal protector J 34014 over end of compressor shaft, and slide the new seal onto the shaft with a rotary motion until it stops. Take care not to dislodge the O-ring. Be sure the seal makes good contact with the O-ring. Disengage the installer from the seal and remove the installer J 23128-A and the seal protector J 34614. NOTICE: Handling and care of seal protector is important. If seal protector is nicked or the bottom flared, the new seal may be damaged during installation. 4. Install the new seal retainer ring with its flat side against the Seal, using Snap-Ring Pliers J 5403. Use the sleeve from O-ring installer J 33011 to press in on the seal retainer ring so that it snaps into its groove. 5. To leak test, install compressor leak test fixture J 39893 on rear head of compressor and connect gage charging lines and J 39500-GM Refrigerant Recovery System. Pressurize suction and high-side of compressor with R-134a Refrigerant. Temporarily install (M9 x 1.25 thread on shaft) nut and, with the compressor in horizontal position, rotate the compressor shaft in normal direction of rotation several turns by hand. Leak test the seal area and correct and leak found. Recover the refrigerant. Remove shaft nut. 6. Remove any excess oil resulting from installing the new seal parts from the shaft and inside the compressor neck. 7. Install the clutch plate and hub assembly as described in minor repair procedures. 8. Reinstall compressor belt and tighten bracket. 9. Evacuate and charge the refrigerant system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor Clutch Diode HVAC > Component Information > Locations Compressor Clutch Diode HVAC: Locations Engine Harness, near A/C Compressor Clutch Connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Compressor Clutch Relay > Component Information > Locations Compressor Clutch Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Control Assembly, HVAC > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Control Assembly, HVAC > Component Information > Diagrams > Electronic A/C Power Module & Heater A/C Programmer Electronic A/C Power Module And Heater A/C Programmer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Control Assembly, HVAC > Component Information > Diagrams > Electronic A/C Power Module & Heater A/C Programmer > Page 8070 Control Assembly: Diagrams Heater and A/C Control Heater And A/C Control (C67) (C1) C201, C302, C303, C351, C400, C401 & C406: Heater & A/C Control (C67) (C2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 99-01-39-004C > Jun > 09 > A/C - Musty Odors Emitted From (HVAC) System Evaporator Core: Customer Interest A/C - Musty Odors Emitted From (HVAC) System TECHNICAL Bulletin No.: 99-01-39-004C Date: June 12, 2009 Subject: Air Conditioning Odor (Install Evaporator Core Dryer Kit and Apply Cooling Coil Coating) Models: 1993-2010 GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 All Equipped with Air Conditioning Supercede: This bulletin is being revised to add the 2009 and 2010 model years. Please discard Corporate Bulletin Number 99-01-39-004B (Section 01 - HVAC). Condition Some customers may comment about musty odors emitted from the Heating, Ventilation and Air Conditioning (HVAC) system at vehicle start-up in hot, humid conditions. Cause This condition may be caused by condensate build-up on the evaporator core, which does not evaporate by itself in high humidity conditions. The odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. There are several other possible sources of a musty odor in a vehicle. A common source is a water leak into the interior of the vehicle or foreign material in the HVAC air distribution system. Follow the procedures in SI for identifying and correcting water leaks and air inlet inspection. The procedure contained in this bulletin is only applicable if the odor source has been determined to be microbial growth on the evaporator core inside the HVAC module. Correction Many vehicles currently incorporate an afterblow function within the HVAC control module software. The afterblow feature, when enabled, employs the HVAC blower fan to dry the evaporator after vehicle shut down and this function will inhibit microbial growth. Technicians are to confirm that the customer concern is evaporator core odor and that the vehicle has the imbedded afterblow feature, as defined in the SI document for that specific vehicle model, model year and specific HVAC option. Refer to SI for enabling the afterblow function. Vehicles being delivered in areas prone to high humidity conditions may benefit from having the afterblow enabled calibration installed prior to any customer comment. Important If the vehicle is not factory equipped with the imbedded afterblow enable feature, it may be added with the Electronic Evaporator Dryer Module Kit (P/N 12497910 or AC Delco 15-5876). Important When installing the Electronic Evaporator Dryer Module, you MUST use the included electrical splice connectors to ensure a proper splice. Complete detailed installation instructions and self testing procedures are supplied with the kit. If necessary, the Electronic Evaporator Dryer Module may be installed underhood if it is protected from extreme heat and water splash areas. To immediately remove the evaporator core odor on all suspect vehicles, it is necessary to eliminate the microbial growth and prevent its re-occurrence. To accomplish this, perform the following procedure: Vehicle and Applicator Tool Preparation 1. The evaporator core must be dry. This may be accomplished by disabling the compressor and running the blower fan on the recirc heat setting for an extended period of time. Note Compressor engagement will cause the evaporator core to remain wet and will prevent full adherence of the Coiling Coil Coating to the evaporator core surfaces. 2. Verify that the air conditioning drain hose is not clogged and place a drain pan beneath the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 99-01-39-004C > Jun > 09 > A/C - Musty Odors Emitted From (HVAC) System > Page 8079 3. Place a protective cover over the carpet below the evaporator core. 4. Remove the cabin air filter, if equipped, and cover the opening prior to applying the Cooling Coil Coating, as the product may clog the filter. If the cabin air filter appears to have little or no remaining life, suggest a replacement to your customer. 5. If the HVAC module has a blower motor cooling tube, be careful NOT TO SPRAY THE COOLING COIL COATING INTO THE BLOWER MOTOR COOLING TUBE. 6. Attach the Flexible Applicator Pressure Spray Tool (J-43810-20A) to a compressed air line operating at 586 kPa (85 psi) to 793 kPa (115 psi). 7. Shake the bottle of Cooling Coil Coating well. Screw the bottle onto the cap on the applicator tool's pick-up tube. Note The pick-up tube is designed for 120 ml (4 oz) and 240 ml (8 oz) bottles and should coil slightly in the bottom of a 120 ml (4 oz) bottle. 8. Use one of the following three methods to apply the Cooling Coil Coating. Important If the Pressure Applicator Spray Tool (J-43810-20A) is not available, the Cooling Coil Coating is also available in an aerosol can (P/N 12377951 (in Canada, 10953503)). Application Through Blower Motor Control Module Opening - Remove the blower motor control module (blower motor resistor). Refer to the applicable procedure in SI. - Clean any debris or foreign material from inside the HVAC module and on the evaporator core surface. - Apply the Cooling Coil Coating directly to the evaporator core through the blower motor blower motor control module (blower motor resistor) opening. - Use the flexible wand to direct the Cooling Coil Coating over the entire evaporator core and surrounding gasket surfaces. - When the application is complete, install the blower motor blower motor control module (blower motor control module). Application Through Blower Motor Opening - Remove the blower motor. Refer to the applicable blower motor removal procedure in SI. - Clean any debris or foreign material from inside the HVAC module and on the evaporator core surface. - Apply the Cooling Coil Coating directly to the evaporator core through the blower motor opening. - Use the flexible wand to direct the Cooling Coil Coating over the entire evaporator core and surrounding gasket surfaces. - When the application is complete, install the blower motor. Application Through a Hole in the HVAC Module - If neither of the two previous application methods are available, it may be necessary to drill a hole in the HVAC module. - Locate an area of the HVAC module between the blower motor and the evaporator core. Drill a 10 mm (3/8 in) hole in the HVAC module. Use caution to keep the drill clear of the evaporator core and the blower motor fan. - With the air distribution vents closed and the blower motor fan speed on HIGH, insert the applicator tool into the hole and spray the Cooling Coil Coating into the airstream toward the evaporator core. - Use a GM approved RTV sealant to plug the hole in the HVAC module. 9. After the Cooling Coil Coating application is complete, start and run the vehicle for approximately 10 minutes, with the compressor disabled, HVAC mode set to Recirculate/Max, heat set to full warm, blower motor fan speed on high, and one window open approximately 12 mm (1/2 in). This cures the Cooling Coil Coating onto the evaporator core surface. 10. While the engine is running, rinse the applicator tool with warm water to prolong the life of the tool. Be sure to spray warm water through the nozzle to rinse out any residual Cooling Coil Coating still in the capillary pick up tube, otherwise it will dry and clog the applicator tool. Also remove the small green valve from the bottle cap and rinse it thoroughly while rolling it between two fingers and then reinstall it. If this valve is clogged , the Cooling Coil Coating will not flow through the applicator tool. 11. Shut off the engine and enable the compressor again. 12. Verify proper HVAC system operation. 13. Remove the protective cover from inside the vehicle. 14. Remove the drain pan from underneath the vehicle. 15. Reinstall the cabin air filter if necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 99-01-39-004C > Jun > 09 > A/C - Musty Odors Emitted From (HVAC) System > Page 8080 Parts Information Important The Cooling Coil Coating listed below is the only GM approved product for use under warranty as an evaporator core disinfectant and for the long term control of evaporator core microbial growth. Warranty Information For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates Evaporator Core: Customer Interest A/C - Odor at Start up in Humid Climates File In Section: 1 - HVAC Bulletin No.: 53-12-12A Date: December, 1996 Subject: Air Conditioning Odor at Start Up in Humid Climates (Disinfect Evaporator Core, Install Delayed Blower Control Package) Models: 1993-96 Passenger Cars (Except GEO) 1993-96 Light Duty Models (Except Tracker) This bulletin is being revised to update the wiring diagrams, add the Corvette (with RPO C60) and delete medium/heavy duty trucks. Please discard Corporate Bulletin Number 53-12-12 (Section 1 HVAC). Condition Some owners may comment on odors emitted from the air conditioning system, primarily at start up in hot, humid climates. Cause This odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. Correction To remove odors of this type, it is necessary to eliminate the microbial growth and prevent its recurrence. To accomplish this, these two procedures must be completed. ^ Deodorize the evaporator core using Deodorizing Aerosol Kit, P/N 12377951 (AC Delco 15-102). ^ Install the new A/C Delayed Blower Control Package, P/N 12370470, (AC Delco 15-8632). The blower control package will enable the blower to run at high speed for five (5) minutes. It will do so approximately fifty (50) minutes after the ignition has been turned off if the compressor had been engaged for four (4) or more minutes prior to shutting off engine. By doing so, the evaporator case and core are dried out, reducing the chances of a recurring A/C odor. Procedure 1. Visually inspect the air conditioning evaporator drain hose for obstructions or working condition. 2. Apply deodorizing aerosol as described in the instructions supplied with the kit. Once the deodorizer has been applied, some of the mixture may overflow from the drain hose. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8085 3. The chart identifies specific instructions for each vehicle. This chart will identify the proper deodorizing procedure, template and wiring diagram. Deodorizing the evaporator case can easily be done by removing the blower motor resistor and tape off opening. The nozzle can now be inserted through a pierced hole in the tape to deodorize the evaporator case. For some of the vehicles specified below, a drilling procedure is identified in the deodorizing instructions. This type of alternative procedure and others can be done by using the referenced templates in the chart. 4. Complete detailed installation instructions are supplied with the blower control package. Important: A. 1996 ONLY (Use blower resistor location for drilling procedure) B. 1994-1996 ONLY Refer to appropriate Service Manual for enabling afterblow feature through on-board diagnostics. Parts Information Parts are currently available from GMSPO. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8086 For vehicles repaired under warranty, use as shown. Figure 1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8087 Figure 2 Figure 3 Figure 4 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8088 Figure 5 Figure 6 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8089 Figure 7 Figure 8 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8090 Figure 9 Figure 10 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8091 Figure 11 Figure 12 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8092 Figure 13 Figure 14 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8093 Figure 15 Figure 16 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8094 Figure 17 Figure 18 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8095 Figure 19 Figure 20 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8096 Figure 21 Figure 22 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8097 Figure 23 Figure 24 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8098 Figure 25 Figure 26 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Customer Interest for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8099 Figure 27 Figure 28 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 99-01-39-004C > Jun > 09 > A/C - Musty Odors Emitted From (HVAC) System Evaporator Core: All Technical Service Bulletins A/C - Musty Odors Emitted From (HVAC) System TECHNICAL Bulletin No.: 99-01-39-004C Date: June 12, 2009 Subject: Air Conditioning Odor (Install Evaporator Core Dryer Kit and Apply Cooling Coil Coating) Models: 1993-2010 GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 All Equipped with Air Conditioning Supercede: This bulletin is being revised to add the 2009 and 2010 model years. Please discard Corporate Bulletin Number 99-01-39-004B (Section 01 - HVAC). Condition Some customers may comment about musty odors emitted from the Heating, Ventilation and Air Conditioning (HVAC) system at vehicle start-up in hot, humid conditions. Cause This condition may be caused by condensate build-up on the evaporator core, which does not evaporate by itself in high humidity conditions. The odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. There are several other possible sources of a musty odor in a vehicle. A common source is a water leak into the interior of the vehicle or foreign material in the HVAC air distribution system. Follow the procedures in SI for identifying and correcting water leaks and air inlet inspection. The procedure contained in this bulletin is only applicable if the odor source has been determined to be microbial growth on the evaporator core inside the HVAC module. Correction Many vehicles currently incorporate an afterblow function within the HVAC control module software. The afterblow feature, when enabled, employs the HVAC blower fan to dry the evaporator after vehicle shut down and this function will inhibit microbial growth. Technicians are to confirm that the customer concern is evaporator core odor and that the vehicle has the imbedded afterblow feature, as defined in the SI document for that specific vehicle model, model year and specific HVAC option. Refer to SI for enabling the afterblow function. Vehicles being delivered in areas prone to high humidity conditions may benefit from having the afterblow enabled calibration installed prior to any customer comment. Important If the vehicle is not factory equipped with the imbedded afterblow enable feature, it may be added with the Electronic Evaporator Dryer Module Kit (P/N 12497910 or AC Delco 15-5876). Important When installing the Electronic Evaporator Dryer Module, you MUST use the included electrical splice connectors to ensure a proper splice. Complete detailed installation instructions and self testing procedures are supplied with the kit. If necessary, the Electronic Evaporator Dryer Module may be installed underhood if it is protected from extreme heat and water splash areas. To immediately remove the evaporator core odor on all suspect vehicles, it is necessary to eliminate the microbial growth and prevent its re-occurrence. To accomplish this, perform the following procedure: Vehicle and Applicator Tool Preparation 1. The evaporator core must be dry. This may be accomplished by disabling the compressor and running the blower fan on the recirc heat setting for an extended period of time. Note Compressor engagement will cause the evaporator core to remain wet and will prevent full adherence of the Coiling Coil Coating to the evaporator core surfaces. 2. Verify that the air conditioning drain hose is not clogged and place a drain pan beneath the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 99-01-39-004C > Jun > 09 > A/C - Musty Odors Emitted From (HVAC) System > Page 8105 3. Place a protective cover over the carpet below the evaporator core. 4. Remove the cabin air filter, if equipped, and cover the opening prior to applying the Cooling Coil Coating, as the product may clog the filter. If the cabin air filter appears to have little or no remaining life, suggest a replacement to your customer. 5. If the HVAC module has a blower motor cooling tube, be careful NOT TO SPRAY THE COOLING COIL COATING INTO THE BLOWER MOTOR COOLING TUBE. 6. Attach the Flexible Applicator Pressure Spray Tool (J-43810-20A) to a compressed air line operating at 586 kPa (85 psi) to 793 kPa (115 psi). 7. Shake the bottle of Cooling Coil Coating well. Screw the bottle onto the cap on the applicator tool's pick-up tube. Note The pick-up tube is designed for 120 ml (4 oz) and 240 ml (8 oz) bottles and should coil slightly in the bottom of a 120 ml (4 oz) bottle. 8. Use one of the following three methods to apply the Cooling Coil Coating. Important If the Pressure Applicator Spray Tool (J-43810-20A) is not available, the Cooling Coil Coating is also available in an aerosol can (P/N 12377951 (in Canada, 10953503)). Application Through Blower Motor Control Module Opening - Remove the blower motor control module (blower motor resistor). Refer to the applicable procedure in SI. - Clean any debris or foreign material from inside the HVAC module and on the evaporator core surface. - Apply the Cooling Coil Coating directly to the evaporator core through the blower motor blower motor control module (blower motor resistor) opening. - Use the flexible wand to direct the Cooling Coil Coating over the entire evaporator core and surrounding gasket surfaces. - When the application is complete, install the blower motor blower motor control module (blower motor control module). Application Through Blower Motor Opening - Remove the blower motor. Refer to the applicable blower motor removal procedure in SI. - Clean any debris or foreign material from inside the HVAC module and on the evaporator core surface. - Apply the Cooling Coil Coating directly to the evaporator core through the blower motor opening. - Use the flexible wand to direct the Cooling Coil Coating over the entire evaporator core and surrounding gasket surfaces. - When the application is complete, install the blower motor. Application Through a Hole in the HVAC Module - If neither of the two previous application methods are available, it may be necessary to drill a hole in the HVAC module. - Locate an area of the HVAC module between the blower motor and the evaporator core. Drill a 10 mm (3/8 in) hole in the HVAC module. Use caution to keep the drill clear of the evaporator core and the blower motor fan. - With the air distribution vents closed and the blower motor fan speed on HIGH, insert the applicator tool into the hole and spray the Cooling Coil Coating into the airstream toward the evaporator core. - Use a GM approved RTV sealant to plug the hole in the HVAC module. 9. After the Cooling Coil Coating application is complete, start and run the vehicle for approximately 10 minutes, with the compressor disabled, HVAC mode set to Recirculate/Max, heat set to full warm, blower motor fan speed on high, and one window open approximately 12 mm (1/2 in). This cures the Cooling Coil Coating onto the evaporator core surface. 10. While the engine is running, rinse the applicator tool with warm water to prolong the life of the tool. Be sure to spray warm water through the nozzle to rinse out any residual Cooling Coil Coating still in the capillary pick up tube, otherwise it will dry and clog the applicator tool. Also remove the small green valve from the bottle cap and rinse it thoroughly while rolling it between two fingers and then reinstall it. If this valve is clogged , the Cooling Coil Coating will not flow through the applicator tool. 11. Shut off the engine and enable the compressor again. 12. Verify proper HVAC system operation. 13. Remove the protective cover from inside the vehicle. 14. Remove the drain pan from underneath the vehicle. 15. Reinstall the cabin air filter if necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 99-01-39-004C > Jun > 09 > A/C - Musty Odors Emitted From (HVAC) System > Page 8106 Parts Information Important The Cooling Coil Coating listed below is the only GM approved product for use under warranty as an evaporator core disinfectant and for the long term control of evaporator core microbial growth. Warranty Information For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates Evaporator Core: All Technical Service Bulletins A/C - Odor at Start up in Humid Climates File In Section: 1 - HVAC Bulletin No.: 53-12-12A Date: December, 1996 Subject: Air Conditioning Odor at Start Up in Humid Climates (Disinfect Evaporator Core, Install Delayed Blower Control Package) Models: 1993-96 Passenger Cars (Except GEO) 1993-96 Light Duty Models (Except Tracker) This bulletin is being revised to update the wiring diagrams, add the Corvette (with RPO C60) and delete medium/heavy duty trucks. Please discard Corporate Bulletin Number 53-12-12 (Section 1 HVAC). Condition Some owners may comment on odors emitted from the air conditioning system, primarily at start up in hot, humid climates. Cause This odor may be the result of microbial growth on the evaporator core. When the blower motor fan is turned on, the microbial growth may release an unpleasant musty odor into the passenger compartment. Correction To remove odors of this type, it is necessary to eliminate the microbial growth and prevent its recurrence. To accomplish this, these two procedures must be completed. ^ Deodorize the evaporator core using Deodorizing Aerosol Kit, P/N 12377951 (AC Delco 15-102). ^ Install the new A/C Delayed Blower Control Package, P/N 12370470, (AC Delco 15-8632). The blower control package will enable the blower to run at high speed for five (5) minutes. It will do so approximately fifty (50) minutes after the ignition has been turned off if the compressor had been engaged for four (4) or more minutes prior to shutting off engine. By doing so, the evaporator case and core are dried out, reducing the chances of a recurring A/C odor. Procedure 1. Visually inspect the air conditioning evaporator drain hose for obstructions or working condition. 2. Apply deodorizing aerosol as described in the instructions supplied with the kit. Once the deodorizer has been applied, some of the mixture may overflow from the drain hose. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8111 3. The chart identifies specific instructions for each vehicle. This chart will identify the proper deodorizing procedure, template and wiring diagram. Deodorizing the evaporator case can easily be done by removing the blower motor resistor and tape off opening. The nozzle can now be inserted through a pierced hole in the tape to deodorize the evaporator case. For some of the vehicles specified below, a drilling procedure is identified in the deodorizing instructions. This type of alternative procedure and others can be done by using the referenced templates in the chart. 4. Complete detailed installation instructions are supplied with the blower control package. Important: A. 1996 ONLY (Use blower resistor location for drilling procedure) B. 1994-1996 ONLY Refer to appropriate Service Manual for enabling afterblow feature through on-board diagnostics. Parts Information Parts are currently available from GMSPO. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8112 For vehicles repaired under warranty, use as shown. Figure 1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8113 Figure 2 Figure 3 Figure 4 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8114 Figure 5 Figure 6 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8115 Figure 7 Figure 8 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8116 Figure 9 Figure 10 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8117 Figure 11 Figure 12 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8118 Figure 13 Figure 14 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8119 Figure 15 Figure 16 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8120 Figure 17 Figure 18 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8121 Figure 19 Figure 20 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8122 Figure 21 Figure 22 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8123 Figure 23 Figure 24 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8124 Figure 25 Figure 26 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Evaporator Core: > 531212A > Dec > 96 > A/C - Odor at Start up in Humid Climates > Page 8125 Figure 27 Figure 28 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Page 8126 Evaporator Core: Service and Repair EVAPORATOR ASSEMBLY Tube And Hose Attachment At Evaporator Assembly REMOVE OR DISCONNECT 1. Refrigerant. ^ Recover refrigerant. See: Service and Repair 2. Hose assembly (9) at evaporator assembly (1). A. Remove nut (43) holding hose assembly (9) to evaporator outlet port. B. Pull hose assembly (9) forward to remove it. C. Seal open end of hose assembly (9) with tape or an approved plastic cap to prevent dirt or moisture contamination. D. If you do not intend to proceed immediately to the following step, seal open evaporator outlet port with tape or an approved plastic cap. E. Discard seal (44). 3. Evaporator tube assembly (10) at evaporator assembly (1). A. Remove nut (39) holding tube assembly (10) to evaporator inlet port. B. Pull tube assembly (10) forward to remove it. C. Seal open evaporator inlet port with tape or an approved plastic cap to prevent dirt or moisture contamination. D. Seal opened end of tube assembly (10) with tape or an approved plastic cap to prevent dirt or moisture contamination. E. Discard seal (40). 4. Studs (42) using a female E-7 TORX® socket. 5. Heater and air conditioning evaporator module lower case. 6. Evaporator mounting bracket bolt/screw and bracket. 7. Evaporator assembly (1). ^ Slide evaporator assembly (1) rearward, then down, to remove it. INSTALL OR CONNECT 1. Evaporator assembly (1). 2. Evaporator mounting bracket and bolt/screw. TIGHTEN ^ Bolt/screw to 1.9 Nm (17 lb. in.). 3. Heater and air conditioning evaporator module lower case. 4. Refrigerant oil. ^ Add 90 ml (3 fluid ounces)of fresh polyalkylene glycol (PAG) refrigerant oil GM P/N 12345923, if evaporator assembly (1) was removed. 5. Studs (42) using a female E-7 TORX® socket. 6. Tube assembly (10) to evaporator inlet port. A. Remove tape or cap from the open end of evaporator inlet port and tube assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Evaporator Core > Component Information > Technical Service Bulletins > Page 8127 B. Coat a new seal (40) with clean mineral base 525 viscosity refrigerant oil GM P/N 12301108 or equivalent and install it. C. Install the tube assembly (10) to evaporator inlet port. D. Install nut (39) at evaporator inlet port. TIGHTEN ^ Nut (39) to 16 Nm (12 lb. ft.). 7. Hose assembly (9) to evaporator outlet port. A. Remove tape or cap from open end of evaporator outlet port and hose assembly. B. Coat a new seal (44) with clean mineral base 525 viscosity refrigerant oil GM P/N 12301108 or equivalent and install it. C. Install hose assembly (9) to evaporator outlet port. D. Install accumulator hose nut (43) at the evaporator outlet port. TIGHTEN ^ Accumulator hose nut (43) to 16 Nm (12 lb. ft.). 8. Evacuate and recharge A/C system. See: Service and Repair 9. Leak-test fittings. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Expansion Block/Orifice Tube > Component Information > Locations Expansion Block/Orifice Tube: Locations Expansion Tube Expansion Tube The plastic tube, also called the orifice tube, is in the enlarged portion at the end of the condenser outlet pipe. Located between the condenser and evaporator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Expansion Block/Orifice Tube > Component Information > Locations > Page 8131 Expansion Block/Orifice Tube: Service and Repair Expansion Tube Expansion Tube Remove or Disconnect Tool Required: J 26549-E Expansion Tube Remover 1. Recover refrigerant. 2. Battery negative cable 3. Condenser-to-evaporator tube fitting. A. Seal open end of evaporator tube with tape or an approved plastic cap to prevent dirt or moisture contamination. B. Discard seal (34). 4. Expansion tube (14) with J 26549-E from condenser outlet pipe. ^ If expansion tube (14) is restricted or plugged, and is difficult to remove, the following procedure is recommended: a. Remove as much residue as possible. b. Carefully apply heat with heat gun, such as a hair dryer or an epoxy dryer near open end of condenser outlet pipe. Do not overheat pipe. c. While applying heat, grip expansion tube (14) with J 26549-E and use a twisting push-pull motion to loosen impacted expansion tube (14) and remove it. Clean ^ Expansion tube (14), if it is to be reused. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Expansion Block/Orifice Tube > Component Information > Locations > Page 8132 A. Blow off any metal chips, flakes, slivers and other contaminants with air hose. B. Clean expansion tube (14) in solvent and dry it. Inspect ^ Expansion tube (14), if it is to be reused. a. Discard if plastic frame is broken. b. Discard if filter screen is torn, damaged or plugged with fine gritty material. c. Discard if brass orifice tube is damaged or plugged. Install or Connect 1. Expansion tube (14). A. Coat expansion tube seal with mineral base 525 viscosity refrigerant oil. B. Insert expansion tube (14) into open end of condenser outlet pipe as shown in Figure 19. Install expansion tube (14) until it stops, indicating proper seal seating. 2. Seal (34) to evaporator tube (10). ^ Coat new seal (34) with mineral base 525 viscosity refrigerant oil GM P/N 12301108 and fit onto evaporator tube (10). 3. Condenser-to~evaporator tube fitting. Tighten ^ Condenser-to-evaporator tube fitting to 24 Nm (18 lb. ft.). 4. Battery negative cable. 5. Charge A/C system. 6. Leak test fittings. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Heater Core > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators Heater Core: Technical Service Bulletins Cooling System, A/C - Aluminum Heater Cores/Radiators INFORMATION Bulletin No.: 05-06-02-001A Date: July 16, 2008 Subject: Information On Aluminum Heater Core and/or Radiator Replacement Models: 2005 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2003-2005 HUMMER H2 Supercede: This bulletin is being revised to update the Warranty Information. Please discard Corporate Bulletin Number 05-06-02-001 (Section 06 - Engine/Propulsion System). Important: 2004-05 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX-COOL(R). Refer to the flushing procedure explained later in this bulletin. The following information should be utilized when servicing aluminum heater core and/or radiators on repeat visits. A replacement may be necessary because erosion, corrosion, or insufficient inhibitor levels may cause damage to the heater core, radiator or water pump. A coolant check should be performed whenever a heater core, radiator, or water pump is replaced. The following procedures/ inspections should be done to verify proper coolant effectiveness. Caution: To avoid being burned, do not remove the radiator cap or surge tank cap while the engine is hot. The cooling system will release scalding fluid and steam under pressure if the radiator cap or surge tank cap is removed while the engine and radiator are still hot. Important: If the vehicle's coolant is low, drained out, or the customer has repeatedly added coolant or water to the system, then the system should be completely flushed using the procedure explained later in this bulletin. Technician Diagnosis ^ Verify coolant concentration. A 50% coolant/water solution ensures proper freeze and corrosion protection. Inhibitor levels cannot be easily measured in the field, but can be indirectly done by the measurement of coolant concentration. This must be done by using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale), or equivalent, coolant tester. The Refractometer uses a minimal amount of coolant that can be taken from the coolant recovery reservoir, radiator or the engine block. Inexpensive gravity float testers (floating balls) will not completely analyze the coolant concentration fully and should not be used. The concentration levels should be between 50% and 65% coolant concentrate. This mixture will have a freeze point protection of -34 degrees Fahrenheit (-37 degrees Celsius). If the concentration is below 50%, the cooling system must be flushed. ^ Inspect the coolant flow restrictor if the vehicle is equipped with one. Refer to Service Information (SI) and/or the appropriate Service Manual for component location and condition for operation. ^ Verify that no electrolysis is present in the cooling system. This electrolysis test can be performed before or after the system has been repaired. Use a digital voltmeter set to 12 volts. Attach one test lead to the negative battery post and insert the other test lead into the radiator coolant, making sure the lead does not touch the filler neck or core. Any voltage reading over 0.3 volts indicates that stray current is finding its way into the coolant. Electrolysis is often an intermittent condition that occurs when a device or accessory that is mounted to the radiator is energized. This type of current could be caused from a poorly grounded cooling fan or some other accessory and can be verified by watching the volt meter and turning on and off various accessories or engage the starter motor. Before using one of the following flush procedures, the coolant recovery reservoir must be removed, drained, cleaned and reinstalled before refilling the system. Notice: ^ Using coolant other than DEX‐COOL(R) may cause premature engine, heater core or radiator corrosion. In addition, the engine coolant may require changing sooner, at 30,000 miles (50,000 km) or 24 months, whichever occurs first. Any repairs would not be covered by your warranty. Always use DEX‐COOL(R) (silicate free) coolant in your vehicle. ^ If you use an improper coolant mixture, your engine could overheat and be badly damaged. The repair cost would not be covered by your warranty. Too much water in the mixture can freeze and crack the engine, radiator, heater core and other parts. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Heater Core > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators > Page 8137 Flushing Procedures using DEX-COOL(R) Important: The following procedure recommends refilling the system with DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. This coolant is orange in color and has a service interval of 5 years or 240,000 km (150,000 mi). However, when used on vehicles built prior to the introduction of DEX-COOL(R), maintenance intervals will remain the same as specified in the Owner's Manual. ^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions. ^ If approved cooling system flush and fill machine is not available, drain the coolant and dispose of properly following the draining procedures in the appropriate Service Manual. Refill the system using clear, drinkable water and run the vehicle until the thermostat opens. Repeat and run the vehicle three (3) times to totally remove the old coolant or until the drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with DEX‐COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M, following the refill procedures in the appropriate Service Manual. If a Service Manual is not available, fill half the capacity of the system with 100% DEX-COOL(R), P/N 12346290 (in Canada, use P/N 10953464), GM specification 6277M. Then slowly add clear, drinkable water (preferably distilled) to the system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and reverify the coolant level. If necessary, add clean water to restore the coolant to the appropriate level. Once the system is refilled, reverify the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. The concentration levels should be between 50% and 65%. Flushing Procedures using Conventional Silicated (Green Colored) Coolant Important: 2004-2005 Chevrolet Aveo (Pontiac Wave, Canada Only) does not use DEX‐COOL(R). The Aveo and Wave are filled with conventional, silicated engine coolant that is blue in color. Silicated coolants are typically green in color and are required to be drained, flushed and refilled every 30,000 miles (48,000 km). The Aveo and Wave are to be serviced with conventional, silicated coolant. Use P/N 12378560 (1 gal) (in Canada, use P/N 88862159 (1 L). Refer to the Owner's Manual or Service Information (SI) for further information on OEM coolant. Important: Do not mix the OEM orange colored DEX-COOL(R) coolant with green colored coolant when adding coolant to the system or when servicing the vehicle's cooling system. Mixing the orange and green colored coolants will produce a brown coolant which may be a customer dissatisfier and will not extend the service interval to that of DEX-COOL(R). Conventional silicated coolants offered by GM Service and Parts Operations are green in color. ^ If available, use the approved cooling system flush and fill machine (available through the GM Dealer Equipment Program) following the manufacturer's operating instructions. ^ If approved cooling systems flush and fill machine is not available, drain coolant and dispose of properly following the draining procedures in appropriate Service Manual. Refill the system using clear, drinkable water and run vehicle until thermostat opens. Repeat and run vehicle three (3) times to totally remove old coolant or until drained coolant is almost clear. Once the system is completely flushed, refill the cooling system to a 50%-60% concentration with a good quality ethylene glycol base engine coolant, P/N 12378560, 1 gal (in Canada, use P/N 88862159 1 L), conforming to GM specification 1825M, or recycled coolant conforming to GM specification 1825M, following the refill procedures in the appropriate Service Manual. If a Service Manual is not available, fill half the capacity of the system with 100% good quality ethylene glycol base (green colored) engine coolant, P/N 12378560 1 gal., (in Canada, use P/N 88862159 1 L) conforming to GM specification 1825M. Then slowly add clear, drinkable water (preferably distilled) to system until the level of the coolant mixture has reached the base of the radiator neck. Wait two (2) minutes and recheck coolant level. If necessary, add clean water to restore coolant to the appropriate level. Once the system is refilled, recheck the coolant concentration using a Refractometer J 23688 (Fahrenheit scale) or J 26568 (centigrade scale) coolant tester, or equivalent. Concentration levels should be between 50% and 65%. Parts Information Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Heater Core > Component Information > Technical Service Bulletins > Cooling System, A/C - Aluminum Heater Cores/Radiators > Page 8138 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Heater Core > Component Information > Service and Repair > With Air Conditioning Heater Core: Service and Repair With Air Conditioning Fig. 21 Heater Core & Evaporator Core 1. Disconnect battery ground cable, then drain cooling system. 2. Remove heater outlet attaching screw. 3. Disconnect heater core pipe fittings, then disengage pipe from fitting. 4. Remove righthand instrument insulator panel attaching screws, then pull panel rearward to disconnect. 5. Remove instrument panel lower reinforcement attaching nut and screw. 6. Disconnect lower evaporator case vacuum electrical connectors. 7. Remove righthand pillar trim finish panel, then roll carpet back to gain access. 8. Remove seven lower evaporator case attaching screws, then remove lower evaporator case. 9. Remove heater core attaching straps and screws, then pull heater core rearward working heater tubes out of seal, Fig. 21. 10. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Heater Core > Component Information > Service and Repair > With Air Conditioning > Page 8141 Heater Core: Service and Repair Without Air Conditioning 1. Disconnect battery ground cable and drain cooling system. 2. Disconnect heater hoses from heater core. Plug core outlets to prevent coolant spillage. 3. Disconnect electrical connections at blower motor and resistor. 4. Detach heater wiring from clip at blower housing cover. 5. Remove blower housing cover attaching screws, then remove blower housing cover. 6. Remove heater core. 7. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment Refrigerant: Technical Service Bulletins A/C - Refrigerant Recovery/Recycling/Equipment Bulletin No.: 08-01-38-001 Date: January 25, 2008 INFORMATION Subject: Information On New GE-48800 CoolTech Refrigerant Recovery/Recharge Equipment Models: 2008 and Prior GM Passenger Cars and Light Duty Trucks (Including Saturn) 2008 and Prior HUMMER H2, H3 2005-2008 Saab 9-7X Attention: This bulletin is being issued to announce the release of GM approved Air Conditioning (A/C) Refrigerant Recovery and Recharging Equipment that meets the new Society of Automotive Engineers (SAE) J2788 Refrigerant Recovery Standards. The ACR2000 (J-43600) cannot be manufactured in its current state after December 2007 and will be superseded by GE-48800. The new J2788 standard does not require that GM Dealers replace their ACR2000 units. ACR2000's currently in use are very capable of servicing today's refrigerant systems when used correctly and can continue to be used. Details regarding the new SAE J2788 standard are outlined in GM Bulletin 07-01-38-004. Effective February 1 2008, new A/C Refrigerant Recovery/Recharging equipment (P/N GE-48800) will be released as a required replacement for the previously essential ACR2000 (J-43600). This equipment is SAE J2788 compliant and meets GM requirements for A/C Refrigerant System Repairs on all General Motors vehicles, including Hybrid systems with Polyolester (POE) refrigerant oil. This equipment will not be shipped as an essential tool to GM Dealerships. In addition, this equipment is Hybrid compliant and designed to prevent oil cross contamination when servicing Hybrid vehicles with Electric A/C Compressors that use POE refrigerant oil. The ACR2000 (J-43600) will need to be retrofitted with a J-43600-50 (Hose - ACR2000 Oil Flush Loop) to be able to perform Hybrid A/C service work. All Hybrid dealers will receive the J-43600-50, with installation instructions, as a component of the Hybrid essential tool package. Dealerships that do not sell Hybrids, but may need to service Hybrids, can obtain J-43600-50 from SPX Kent Moore. Refer to GM Bulletin 08-01-39-001 for the ACR2000 Hose Flush procedure. The High Voltage (HV) electric A/C compressor used on Two Mode Hybrid vehicles uses a Polyolester (POE) refrigerant oil instead of a Polyalkylene Glycol (PAG) synthetic refrigerant oil. This is due to the better electrical resistance of the POE oil and its ability to provide HV isolation. Failure to flush the hoses before adding refrigerant to a Hybrid vehicle with an electric A/C compressor may result in an unacceptable amount of PAG oil entering the refrigerant system. It may cause a Battery Energy Control Module Hybrid Battery Voltage System Isolation Lost Diagnostic Trouble Code (DTC P1AE7) to be set. Additionally, the A/C system warranty will be voided. Warranty Submission Requirements The Electronically Generated Repair Data (snapshot summary) and printer functions have been eliminated from the GE-48800. The VGA display and temperature probes were eliminated to reduce equipment costs. As a result, effective immediately the 18 digit "Snapshot/Charge Summary" code is no longer required for Air Conditioning (A/C) refrigerant system repairs that are submitted for warranty reimbursement. The charge summary data from before and after system repairs will continue to required, but documented on the repair order only. Both high and low pressures and the recovery and charge amounts should be noted during the repair and entered on the repair order. If using ACR2000 (J-43600), the "Snapshot/Charge Summary" printouts should continue to be attached to the shops copy of the repair order. The labor codes that are affected by this requirement are D3000 through D4500. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8146 Refrigerant: Technical Service Bulletins A/C - Contaminated R134A Refrigerant Bulletin No.: 06-01-39-007 Date: July 25, 2006 INFORMATION Subject: Contaminated R134a Refrigerant Found on Market for Automotive Air-Conditioning Systems Models: 2007 and Prior GM Passenger Cars and Trucks (including Saturn) 2007 and Prior HUMMER H2, H3 2007 and Prior Saab 9-7X Attention: This bulletin should be directed to the Service Manager as well as the Parts Manager. Commercially Available Contaminated R134a Refrigerant Impurities have been found in new commercially available containers of R134a. High levels of contaminates may cause decreased performance, and be detrimental to some air-conditioning components. Accompanying these contaminates has been high levels of moisture. Tip: Excessive moisture may cause system concerns such as orifice tube freeze-up and reduced performance. Industry Reaction: New Industry Purity Standards Due to the potential availability of these lower quality refrigerants, the Society of Automotive Engineers (SAE), and the Air Conditioning and Refrigeration Industry (ARI) are in the process of instituting reliable standards that will be carried on the labels of future R134a refrigerant containers. This identifying symbol will be your assurance of a product that conforms to the minimum standard for OEM Automotive Air-Conditioning use. How Can You Protect Yourself Today? It is recommended to use GM or ACDelco(R) sourced refrigerants for all A/C repair work. These refrigerants meet General Motors own internal standards for quality and purity, insuring that your completed repairs are as good as the way it left the factory. Parts Information The part numbers shown are available through GMSPO or ACDelco(R). The nearest ACDelco(R) distributor in your area can be found by calling 1-800-223-3526 (U.S. Only). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8147 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8148 Refrigerant: Technical Service Bulletins A/C - Refrigerant Recovery/Recharge Equipment File In Section: 01 - HVAC Bulletin No.: 99-01-38-006A Date: May, 2000 WARRANTY ADMINISTRATION Subject: J-43600 ACR 2000 Essential Refrigerant Recovery/Recharge Equipment Models: 1993-2000 Passenger Cars and Light Duty Trucks with R-134a Refrigerant This bulletin is being revised to change the effective date and to update the text. Please discard Corporate Bulletin Number 99-01-38-006 (Section 01 - HVAC). Effective June 1, 2000, the use of J-43600 ACR 2000 will be required on all repairs that require A/C system recovery and are reimbursable by GM. Additionally, GM highly recommends that J-43600 ACR 2000 be used on all GM cars and trucks for customer paid A/C repairs. Important: Also effective June 1, 2000, the "Add" time for all air conditioning recovery is revised to 0.5 hours for front systems and 0.7 hours for front/rear dual systems (RPO C69 or C34). After June 1, 2000, all air conditioning claims submitted with the 0.9 hours "Add" time will be rejected for "labor hours excessive". After the completion of repairs (charging), the ACR 2000 will prompt the user to perform a snapshot of the air conditioning system operating data. The snapshot includes: ^ Maximum high side pressure. ^ Minimum low side pressure. ^ Duct outlet temperatures (2). ^ Refrigerant purity information. This information is captured on a paper printout and in a warranty code. For all GM paid repairs, the paper printout should be attached to the shop copy of the repair order. The warranty code must be submitted in the warranty claim information in the comments field. The code enables the reporting of valuable information about the repair to GM for product quality improvement. Claims submitted without this information may be subject to review and subsequent debit. The required use of J-43600 ACR 2000 raises the question of the acceptable uses for any existing recovery/recycle equipment that GM dealers are currently using. GM recognizes that many of the previously essential ACR4's are reaching the end of their useful life. There are several alternatives for existing equipment that may be considered: ^ Use the existing equipment as customer paid recovery only equipment. Example: Collision repair area. ^ Use the existing equipment as a scavenger unit for contaminated A/C systems. ^ Sell the existing units to repair facilities outside the GM dealer network. ^ Discontinue the use of the existing units if the repair/maintenance costs exceed the value of the equipment. ^ Donate the existing equipment to local technical schools. ^ Dedicate the ACR4 to A/C system flushing, using the J-42939 Flush Adapter. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8149 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8150 Technical Service Bulletin # 631209 Date: 960501 A/C - R12 or R134a Service Recommendations File In Section: 1 - HVAC Bulletin No.: 63-12-09 Date: May, 1996 INFORMATION Subject: Service Issues for Vehicles with R12 or R134a Air Conditioning Systems Models: 1988-96 Passenger Cars and Trucks R12 Service Recommendations As you know, production of R12 refrigerant ceased on December 31, 1995. Although R12 will no longer be manufactured, there is a reserve supply of R12 available. This reserve, along with strict A/C repair service adherence to proper refrigerant recycling procedures, should assure continued availability to meet consumers' needs. R12 can and should continue to be used to service vehicles built with R12 A/C systems as long as it is available. If R12 is no longer available or affordable, a system retrofit utilizing R134a is recommended. R134a IS THE ONLY SUBSTITUTE REFRIGERANT RECOMMENDED BY GM FOR USE IN GM VEHICLE A/C SYSTEMS, AND THEN ONLY AFTER FOLLOWING THE PROPER RETROFIT PROCEDURES FOR THE SPECIFIC MODEL. All new vehicle manufacturers have chosen R134a for retrofit. One of the key reasons is to protect both the service industry and consumers from the high costs that would result from purchasing equipment necessary to service multiple refrigerants. This position also reduces the threat of recycled refrigerant contamination. GM currently offers a simple, low cost R12 to R134a retrofit on many of its late model, front wheel drive passenger cars. Dealers should discuss this capability with owners of these specific models, listed in Retrofit Corporate Bulletin # 43-12-07D, whenever a repair to the A/C refrigerant system is required. Early retrofit of these specific models will aid in prolonging availability of the R12 supply and provide dealer service technicians the opportunity to become more familiar with the proper procedures for performing a retrofit. Remember - R12 and R134a refrigerant are not interchangeable! They cannot be mixed together. In fact, despite the claims of some refrigerant manufacturers, no proposed R12 refrigerant substitute can be added to, mixed with or used to "top off" an R12 system. Under provisions of law covering the service of refrigerants, mixing dissimilar refrigerant products during service is prohibited. To Summarize GM R12 Service Policy 1. Service R12 vehicles with good quality new or recycled R12 as long as it is available. 2. Purchase R12 from a reliable supplier. GMSPO has a supply of high quality R12 available. Dealers are requested to use only R12 supplied by GMSPO for warranty repairs. This high quality refrigerant will insure system performance and avoid the possibility of introducing contaminated material into the customer's A/C system. 3. Carefully test recovered R12 using the PureGuard monitor. On recovery equipment not protected by the PureGuard, always test the recovery cylinder prior to recharging a vehicle A/C system. 4. Discuss the R12 to R134a retrofit option with owners of GM vehicles listed in Retrofit Corporate Bulletin # 43-12-07D. Provide owner with a copy of the pamphlet "Converting Your Auto Air Conditioning System to Use the New Refrigerant". 5. Become familiar with retrofit procedures and exercise care in the handling of dissimilar refrigerants to prevent contamination. R134A Service Recommendations When servicing a previously retrofitted vehicle, there is concern that if all of the R12 is not completely removed prior to the retrofit procedure, it could contaminate your R134a equipment and recovery tank when a subsequent A/C repair is performed. Although the number of retrofits being performed today is minimal, the volume will increase as R12 prices rise. GM Service Technology Group is in the process of field testing a new R134a refrigerant purity tester similar to the PureGuard R12 refrigerant tester you now use. This new tool will mount to your ACR4 R134a Recovery Recycle and Recharge cart and sample all R134a refrigerant prior to recovery. It is expected that testing of this tool will be completed this year. This new tool, the Pureguard 2, will also test vehicles and your recycle tank for air contamination, which is threatening A/C system performance. High levels of air have been found in the recovery tanks on a number of R12 and R134a recovery carts. Air contamination is caused by improper recovery Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8151 procedures and short-cutting refrigerant recycling times. Use the following procedure for testing and correcting air contamination in your A/C service equipment. 1. Make certain that the ACR4 equipment has not been used for at least 12 hours. It is recommended that the equipment be left in an area where the temperature will remain constant overnight to allow the temperature of the refrigerant in the tank to stabilize. 2. Record the surrounding air temperature next to the ACR4 refrigerant tank. Important: A major assumption is that the ambient air temperature next to the tank represents the refrigerant temperature in the tank. Failure to take care in measuring the temperature could result in unnecessary work. 3. Close both liquid (blue) and vapor (red) valves on the ACR4 tank. 4. Disconnect low side (blue) service hose from the back of the ACR4. 5. Slowly disconnect the tank vapor hose (red) from the back of the ACR4 and connect it to the low side service port. 6. Open the vapor (red) valve on the tank and record the tank pressure on the low side gage. 7. Restore hoses to the original position. 8. Referring to the Table, find the ambient temperature measured in Step 2. Compare the pressure reading from Step 6 to the "maximum allowable pressure". If the pressure reading from Step 6 is less than the "maximum allowable pressure", no further action is necessary. Important: The closer the tank pressure is to the desired tank pressure, the better the A/C system will perform. 9. If the pressure reading from Step 6 exceeds the maximum allowable pressure from the Table, open both tank valves and operate the ACR4 through 4 or 5 evacuation cycles. This will activate the automatic air purge to lower the tank pressure. Important: Station should not be connected to vehicle. 10. Repeat the tank pressure checking procedure the next day to determine if the pressure has been reduced to acceptable levels. If the tank pressure has been reduced but is not acceptable, cycle with ACR4 through more evacuation cycles and recheck the next day. Continue process until acceptable pressure is obtained. If the tank pressure is not reduced through the evacuation cycling, then Kent-Moore should be contacted at 1-800-345-2233. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8152 Refrigerant: Technical Service Bulletins A/C - R134a Leak Detection With Tracer Dye File In Section: 1 - HVAC Bulletin No.: 43-12-15 Date: November, 1994 Subject: R134a Leak Detection with Tracer Dye Models: All 1993-95 Vehicles with OEM R134a Systems All R12 Vehicles Retrofitted to R134a Systems R134a refrigerant is uniquely different from R12 refrigerant and requires some changes in the repair methods, tools and materials used in A/C service. Two important differences between R134a and R12 which affect the technicians ability to locate refrigerant leaks are: 1. The R134a molecule is smaller than the R12 molecule and therefore will leak through smaller openings. For the same size opening the smaller R134a molecule will leak out faster than the R12. 2. R134a refrigerant does not contain chlorine which the older R12 electronic leak detectors found very easy to identify. Many of today's electronic leak detectors have difficulty locating small R134a refrigerant leaks. In order to insure the highest quality in A/C system service, the J 39400 electronic leak detector was released as an essential tool for all GM dealers. This is the only refrigerant leak detector approved by GM for service on R134a vehicles. If maintained properly (Reference Bulletin No. 431218) and used in accordance with Service Manual procedures, the J 39400 will provide the most accurate and efficient method of locating R134a refrigerant leaks under most conditions. If the technician cannot find the leak with the J 39400 and the system is known to have lost charge, a new fluorescent leak tracer dye Kent-Moore* P/N J 41447, has been released that mixes with the R134a PAG oil. This dye is detectable through the use of an ultraviolet (black) light and glows yellow/green at the leak location (similar to using dye in engine leak detection). J 41447 IS THE ONLY APPROVED DYE BY GENERAL MOTORS. Not all R134a dyes are compatible with GM's PAG oil. Some dyes decrease the oil viscosity or chemically react with the oil. Use of alternate products may affect system reliability and cause premature compressor failure. Note: THIS DYE IS NOT TO BE USED IN R-12 SYSTEMS. Unlike mineral oil, the R134a PAG oil has special properties the technician should keep in mind. 1. PAG oil is water soluble and traces of PAG oil found at leaking joints are subject to "washing out". Condensation on refrigerant lines or the evaporator core may wash the PAG oil and leak dye off the line or off the core and out the condensate drain. This can make some leaks harder to find using the dye detector. Fluorescence at the drain opening would indicate a core leak. 2. Use of the R134a tracer dye requires time. Depending upon the leak rate, it may take between 15 minutes and 7 days for the leak to become visible. 3. The dye, mixed with the PAG oil, is retained in the system and is detectable for 2+ years. Do not double or triple charge the system with dye as this may cause reliability concerns. Use only the 1/4 oz. charge. The dye has a refrigerant leak detection notice sticker included with the package. Complete the sticker information and place near the charge label. Dye Injection R-134a dye can be injected two ways: 1. With the A/C system charged, use the instructions provided with the new R134a leak dye injection tool, J 41436. 2. With A/C system discharged, add dye into the newly replaced component assembly. It is important to note that it is normal to find oil traces at the compressor shaft seal during compressor operation, some oil will hydraulically seep past the shaft seal. This does not mean that the shaft seal is defective or that the refrigerant has leaked. Refrigerant leaks at the shaft seal should be verified with the electronic leak detector (J 39400) following the procedure detailed in the Service Manual. If, however, the amount of oil is excessive, the shaft seal is suspect and should be replaced. (For example, refrigerant oil has coated the clutch plate edge at gap between clutch and pulley, or oil slinging has occurred-oil line shows on underside of hood, etc.). Also, after working on A/C components with dye, it is important to wipe the joint and/or access ports clean of any residual dye with GM solvent (GM Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > A/C - Refrigerant Recovery/Recycling/Equipment > Page 8153 P/N 1050436) to prevent false diagnosis at a later point. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Parts Information GM solvent, P/N 1050436, is currently available from GMSPO. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Technical Service Bulletins > Page 8154 Refrigerant: Specifications Refrigerant Capacity, Lbs. ................................................................................................................... ................................................ 0.79 kg. (1 lb. 12 oz.) Refrigerant Type .................................................................................................................................. ...................................................................... R-134a Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Description and Operation > Refrigerant R-12 Refrigerant: Description and Operation Refrigerant R-12 DESCRIPTION It is colorless and odorless both as a gas and a liquid. Since it boils (vaporizes) at -21.7° F, it will usually be in a vapor state when being handled in a repair shop. But if a portion of the liquid coolant should come in contact with the hands or face, note that its temperature momentarily will be at least -22° F. WARNING: Protective goggles should be worn when opening any refrigerant lines. If liquid coolant does touch the eyes, bathe the eyes quickly in cold water, then apply a bland disinfectant oil to the eyes. See an eye doctor. WARNING: When checking a system for leaks with a torch type leak detector, do not breathe the vapors coming from the flame. Do not discharge refrigerant in the area of a live flame. A poisonous phosgene gas is produced when R-12 is burned. While the small amount of gas produced by a leak detector is not harmful unless inhaled directly at the flame, the quantity of refrigerant released into the air when a system is purged can be extremely dangerous if allowed to come into contact with an open flame. WARNING: Never allow the temperature of refrigerant drums to exceed 125° F. The excessive increase in temperature will cause a corresponding increase in pressure which may cause the safety plug to release or the drum to burst. If it is necessary to heat a drum of refrigerant when charging a system, the drum should be placed in water no hotter than 125° F. Never use a blow torch or other open flame. If possible, a pressure release mechanism should be attached before the drum is heated. When connecting and disconnecting service gauges on an A/C system, ensure gauge hand valves are fully closed and that compressor service valves, if equipped, are in the back-seated (fully counterclockwise) position. Do not disconnect gauge hoses from service port adapters, if used, while gauges are connected to A/C system. To disconnect hoses, always remove adapter from service port. Do not disconnect hoses from gauge manifold while connected to A/C system, as refrigerant will be rapidly discharged. After disconnecting gauge lines, check the valve areas to be sure service valves are correctly seated and Schrader valves, if used, are not leaking. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant > Component Information > Description and Operation > Refrigerant R-12 > Page 8157 Refrigerant: Description and Operation Refrigerant-134a R-134a refrigerant is a non toxic, nonflammable, clear and odorless liquefied gas. CAUTION: R-134a refrigerant is not compatible with R-12 refrigerant. Even small amounts of R-12 in a R-134a system will cause lubricant contamination, compressor failure or improper A/C performance. Never add R-12 to a R-134a system. WARNING: Avoid breathing R-134a refrigerant and lubricant vapor or mist. Exposure may irritate eyes, nose and throat. Use only approved service equipment to discharge R-134a systems. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant Oil > Component Information > Technical Service Bulletins > A/C - New PAG Oil Refrigerant Oil: Technical Service Bulletins A/C - New PAG Oil Bulletin No.: 02-01-39-004B Date: November 16, 2005 INFORMATION Subject: New PAG Oil Released Models: 2006 and Prior GM Passenger Cars and Trucks (Including Saturn) 2003-2006 HUMMER H2 2006 HUMMER H3 2005-2006 Saab 9-7X Built With R-134a Refrigeration System All Air Conditioning Compressor Types (Excluding R4 and A6 Type Compressors) Supercede: This bulletin is being revised to change the PAG oil part number used for R4 and A6 compressors with R-134a refrigerant systems. Please discard Corporate Bulletin Number 02-01-39-004A (Section 01 - HVAC). All General Motors vehicles built with R-134a refrigerant systems shall now be serviced with GM Universal PAG Oil (excluding vehicles equipped with an R4 or A6 compressor). R4 and A6 compressors with R-134a refrigerant systems shall use PAG OIL, GM P/N 12356151 (A/C Delco part number 15-118) (in Canada, use P/N 10953486). Important: The PAG oil referenced in this bulletin is formulated with specific additive packages that meet General Motors specifications and use of another oil may void the A/C systems warranty. Use this new PAG oil when servicing the A/C system on the vehicles listed above. Oil packaged in an 8 oz tube should be installed using A/C Oil Injector, J 45037. Refer to the HVAC Section of Service Information for detailed information on Oil Balancing and Capacities. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant Oil > Component Information > Specifications > Capacity Specifications Refrigerant Oil: Capacity Specifications Compressor Model [02] ....................................................................................................................... ........................................................... HD6/HR6-HE Oil Charge (FL. Oz.) When Replacing Component Compressor ......................................................................................................................................... ............................................................................. [03] Evaporator ........................................................................................................................................... ................................................................................. 3 Condenser ...................................................... .............................................................................................................................................................. ........ 1 Accumulator ............................................................................................................................. ......................................................................................... 3.5 [02] Fixed displacement compressor. [03] Drain oil from old compressor and measure, then drain new compressor. If more than one ounce is drained from old compressor, add same amount to new compressor. If less than one ounce is drained from compressor, add two ounces. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant Oil > Component Information > Specifications > Capacity Specifications > Page 8164 Refrigerant Oil: Fluid Type Specifications REFRIGERANT OIL TYPE ^ R-134a PAG (Polyalkaline Glycol) synthetic refrigerant oil (GM Part No. 12345923) or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant Pressure Sensor / Switch, HVAC > Component Information > Locations > A/C Compressor Pressure Cycling Switch Refrigerant Pressure Sensor / Switch: Locations A/C Compressor Pressure Cycling Switch Engine Harness/U/Hood Electrical Center, Right Side Attached to A/C accumulator, RH rear of Engine Compartment RH Rear Engine Compartment attached to A/C Accumulator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Refrigerant Pressure Sensor / Switch, HVAC > Component Information > Locations > A/C Compressor Pressure Cycling Switch > Page 8169 Refrigerant Pressure Sensor / Switch: Locations A/C Refig Press Sensor Component Location - Pictorial View In High Pressure Line, below Coolant Reservoir Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Relays and Modules - HVAC > Blower Motor Relay > Component Information > Locations Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Relays and Modules - HVAC > Blower Motor Relay > Component Information > Locations > Page 8174 LO Blower Relay, Rear Defog Relay And HI Blower Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Relays and Modules - HVAC > Compressor Clutch Relay > Component Information > Locations Compressor Clutch Relay: Locations Underhood Electrical Center Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Air Conditioning Switch > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Ambient Temperature Sensor / Switch HVAC > Component Information > Locations > Inside Air Temperature Sensor Ambient Temperature Sensor / Switch HVAC: Locations Inside Air Temperature Sensor Instrument Panel Carrier, above Glove Box. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Ambient Temperature Sensor / Switch HVAC > Component Information > Locations > Inside Air Temperature Sensor > Page 8186 Ambient Temperature Sensor / Switch HVAC: Locations Outside Air Temperature Sensor Attached to Hood Latch Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Blower Motor Switch > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Blower Motor Switch > Component Information > Locations > Page 8190 Heater And A/C Blower Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Refrigerant Pressure Sensor / Switch, HVAC > Component Information > Locations > A/C Compressor Pressure Cycling Switch Refrigerant Pressure Sensor / Switch: Locations A/C Compressor Pressure Cycling Switch Engine Harness/U/Hood Electrical Center, Right Side Attached to A/C accumulator, RH rear of Engine Compartment RH Rear Engine Compartment attached to A/C Accumulator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Refrigerant Pressure Sensor / Switch, HVAC > Component Information > Locations > A/C Compressor Pressure Cycling Switch > Page 8195 Refrigerant Pressure Sensor / Switch: Locations A/C Refig Press Sensor Component Location - Pictorial View In High Pressure Line, below Coolant Reservoir Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Sensors and Switches - HVAC > Solar Sensor, HVAC > Component Information > Locations Solar Sensor: Locations Near center of I/P Upper Trim Pad (in Defroster Grille) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Solar Sensor, HVAC > Component Information > Locations Solar Sensor: Locations Near center of I/P Upper Trim Pad (in Defroster Grille) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Vacuum Harness HVAC > Component Information > Locations RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Vacuum Solenoid Valve HVAC > Component Information > Locations Rear View Of Center Instrument Panel (With C67 Or C68) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Heating and Air Conditioning > Vacuum Solenoid Valve HVAC > Component Information > Locations > Page 8208 Vacuum/Electric Solenoid Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming Air Bag(s) Arming and Disarming: Service and Repair Air Bag Disarming and Arming Disabling the SIR System The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Ensure front wheels are pointed straight ahead. 2. Turn ignition switch to LOCK position and remove SIR or AIR BAG fuse. 3. Remove Connector Position Assurance (CPA), then disconnect both yellow 2-way SIR electrical connectors at base of steering column. 4. Wait at least 2 minutes before proceeding with diagnosis or service. Enabling the SIR System 1. Connect both 2-way yellow connectors at base of steering column. 2. Install Connector Position Assurance (CPA). 3. Install SIR or AIR BAG fuse into fuse block. 4. Turn ignition to the RUN position and ensure that the "Inflatable Restraint lamp flashes seven to nine times and then turns off. If lamp does not operate as specified, refer to Testing And Inspection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming > Page 8215 Air Bag(s) Arming and Disarming: Service and Repair General Service Precautions CAUTION; When performing service on or around SIR components or SIR wiring, follow the procedures to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure Air Bag: Technical Service Bulletins Air Bag - Module Shipping/Return Procedure File In Section: 9 - Accessories Bulletin No.: 31-90-04A Date: September, 1996 Subject: Supplemental Inflatable Restraint (SIR) Module Shipping/Return Procedure Models: 1993-97 Passenger Cars and Trucks - Equipped with Supplemental Inflatable Restraint (SIR) Modules EXCEPT THE MODELS AND YEARS AS LISTED This bulletin is being revised to update the: models and years affected, the contact telephone numbers and the hazardous classification rating. Various areas of the text and the attachments have also been revised. Please discard Corporate Bulletin Number 319004 (Group Reference Accessories). This bulletin outlines the return procedure for undeployed Supplemental Inflatable Restraint (SIR) modules. Undeployed SIR modules in all vehicles (except models indicated), removed for warranty purposes, are to be returned to Delphi Interior and Lighting Systems, General Motors Corporation. This bulletin outlines procedures that all dealers must follow for shipping undeployed airbag modules. This bulletin is in effect and should be retained at all times at the dealership until superseded by a subsequent bulletin. This return program does NOT apply to dealers in Alaska, Hawaii, US Territories, and foreign countries. SIR modules replaced outside the continental United States should be deployed and disposed of following the procedure outlined in Corporate Bulletin Number 319003R. All other modules (i.e., out of warranty or car scrapped) should be disposed of per Corporate Bulletin Number 319003R. Important: If a vehicle is the subject of a Preliminary Investigation (GM-1241), DO NOT ALTER the SIR system until cleared by the Zone Service Representative. An SIR module returned following a 1241 investigation must be clearly designated by: 1. Indicating on the REPAIR ORDER copy inside the box "SUBJECT TO 1241". 2. Indicating the VIN and vehicle owner on the REPAIR ORDER. 3. Sending photocopies of the REPAIR ORDER to: a. The appropriate Zone service Representative b. Cigna Company GM Central Claims Unit 485 W. Milwaukee Suite 690 Detroit, MI 48202 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8220 Mailing Address: P.O. Box 02489, Detroit, MI 48202 Questions related to handling of 1241 associated SIR modules may be answered by calling: Cigna Company - GM Central Claims Unit, 1-800-888-1491. The U.S. Department of Transportation (DOT) Hazardous Materials Regulations classify SIR modules as the following: ^ Proper Shipping Name: Air Bag Modules ^ Hazardous Class: Class 9 - Air Bag Failure to comply with DOT regulations will result in civil penalties of up to $10,000 per violation or criminal penalties of up to $25,000 per violation and imprisonment. Return Procedure for Supplemental Inflatable Restraint Modules (Undeployed Modules Only) All undeployed SIR modules in all vehicles (except as indicated in the models section of this bulletin), removed for warranty purposes, are to be returned to Delphi Interior and Lighting Systems, General Motors. The following procedure should be followed when returning SIR modules from any location within the continental United States. 1. Packaging Requirements Return undeployed SIR modules in the same carton that was received with the new replacement module. Do not use any carton that has been damaged to the extent that the product will not be protected during the shipment. If you need a replacement carton, contact Delphi Interior and Lighting Systems at (513) 356-2426. ENCLOSE A COPY OF THE REPAIR ORDER, detailing the reason(s) for the SIR module replacement. Close and secure the carton with packaging tape (transparent tape is recommended). All existing labels and markings on the carton must be visible. Important: DO NOT staple container. DO NOT cover any portion of the black and white "Class 9" label or any markings on the carton. 2. Package Labels and Markings Add the names and addresses for the consignee and the consignor. The method of closure cannot interfere with the labels or the markings on the package (see Attachments "A" - Driver Side, and "D" - Passenger Side). 3. Shipping Paper (UPS Hazardous Material Label and Shipper's Certification) The following items on the shipping papers must be completed with the same information as enclosed with the replacement SIR module when received: proper shipping name, hazard class, identification number, packaging group number, "EX" number, and emergency response telephone number. The remaining information should be completed in accordance with Attachments "B" and "E" (Driver Side) and "C" and "F" (Passenger Side). A copy of the emergency response guidelines (see Attachment "G") is enclosed with the replacement SIR module and must be attached to the shipping papers you complete for the SIR module being shipped. 4. Transportation All SIR modules are to be returned using United Parcel Service (UPS) which will require the sender to pre-pay the freight charges. If difficulties arise, contact Delphi Interior and Lighting Systems, General Motors at (513) 356-2426. 5. RETURN ALL SUPPLEMENTAL INFLATABLE RESTRAINT MODULES (EXCEPT FOR THOSE MODELS LISTED IN THIS BULLETIN) TO THE FOLLOWING ADDRESS: Delphi Interior and Light Systems 3249 McCall Avenue Dayton, OH 45417 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8221 ATTACHMENT A DRIVER AIRBAG Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8222 ATTACHMENT B DRIVER SIDE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8223 ATTACHMENT C DRIVER SIDE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8224 ATTACHMENT D PASSENGER AIRBAG Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8225 ATTACHMENT E PASSENGER SIDE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8226 ATTACHMENT F PASSENGER SIDE Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Technical Service Bulletins > Air Bag - Module Shipping/Return Procedure > Page 8227 ATTACHMENT G Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Locations > Component Locations Air Bag: Component Locations RH I/P Steering Wheel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Locations > Component Locations > Page 8230 RH I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Locations > Page 8231 Air Bag: Description and Operation DESCRIPTION The inflator modules consist of an inflatable bag and an inflator (a canister of gas-generating material and an initiating device). OPERATION When the vehicle is in a frontal crash of sufficient force, the SDM or arming sensor causes current to flow through the deployment loops. Current passing through the initiator ignites the material in the inflator module. The gas produced from this reaction rapidly inflates the air bag. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Service and Repair > Driver's Inflator Module Air Bag: Service and Repair Driver's Inflator Module WARNING: The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Disarm system as described in Air Bag System Disarming & Arming. 2. Remove module attaching bolts from rear of steering wheel. 3. Rotate horn lead 1/4 turn and disconnect. 4. Disconnect inflator module electrical connector, then remove module from steering wheel. 5. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition switch to On position and verify that the Air Bag or SIR warning lamp flashes seven to nine times and then turns off. If lamp does not respond as specified, refer to System Diagnosis Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag > Component Information > Service and Repair > Driver's Inflator Module > Page 8234 Air Bag: Service and Repair Passenger's Inflator Module WARNING: The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Disarm system as described in Air Bag System Disarming & Arming. 2. Remove instrument panel upper trim pad. 3. Remove Connector Position Assurance (CPA), then disconnect module electrical connector. 4. Remove inflator module attaching bolts, then the inflator module from vehicle. 5. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition switch to On position and verify that the AIR BAG or SIR warning lamp flashes seven to nine times and then turns off. If lamp does not respond as specified, refer to System Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag Control Module > Component Information > Locations > System Component Locations Description Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag Control Module > Component Information > Locations > System Component Locations > Page 8239 LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag Control Module > Component Information > Locations > Page 8240 Inflatable Restraint Diagnostic Energy Reserve (With Sensor) Module (SDM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Air Bag Control Module > Component Information > Locations > Page 8241 Air Bag Control Module: Description and Operation DESCRIPTION The Sensing and Diagnostic Module (SDM) performs several system functions. These functions include energy reserve, air bag deployment, malfunction detection, malfunction diagnosis, driver notification, frontal crash detection and frontal crash recording. OPERATION The SDM contains a sensing device which converts vehicle velocity changes to an electrical signal. The electrical signal generated is processed by the SDM and then compared to a value stored in memory. When the generated signal exceeds the stored value, additional signals are compared to signals stored in memory. When two of the generated signals exceed the stored values or when one of the generated signals exceeds the stored value and the forward discriminating sensor closes, the SDM will cause current to flow through the inflator modules deploying the air bags. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Clockspring Assembly / Spiral Cable, Air Bag > Component Information > Locations > Component Locations Steering Wheel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Clockspring Assembly / Spiral Cable, Air Bag > Component Information > Locations > Component Locations > Page 8246 Clockspring Assembly / Spiral Cable: Connector Locations Lower LH Side Of Steering Column RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Clockspring Assembly / Spiral Cable, Air Bag > Component Information > Locations > Component Locations > Page 8247 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Clockspring Assembly / Spiral Cable, Air Bag > Component Information > Locations > Page 8248 Clockspring Assembly / Spiral Cable: Description and Operation DESCRIPTION The SIR coil assembly consists of two current carrying coils. They are attached to the steering column and allow rotation of the steering wheel while maintaining continuous contact of the driver deployment loop to the driver's inflator module. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Clockspring Assembly / Spiral Cable, Air Bag > Component Information > Locations > Page 8249 Clockspring Assembly / Spiral Cable: Service and Repair WARNING: The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Disarm system as described in Air Bag System Disarming & Arming. 2. Position front wheels in the straight ahead position. 3. Remove driver's air bag as described in Air Bag Module. 4. Disconnect electrical connectors. 5. Place alignment marks on steering wheel hub and steering column shaft for installation reference. 6. Remove steering wheel retaining nut. 7. Using suitable steering wheel puller, remove steering wheel. 8. Place ignition switch in the Lock position, to retain coil assembly in the centered position. 9. Remove coil assembly retaining ring. 10. Remove lock plate, turn signal canceling cam and upper bearing spring, inner race seat and inner race. 11. Place turn signal lever in righthand turn position, then remove multi-function lever and hazard flasher warning knob. 12. Remove turn signal switch lever attaching screw, then the lever. 13. Remove turn signal switch attaching screws and allow switch to hang from wire. 14. Disconnect SIR coil connector from turn signal switch electrical connector. 15. Using mechanics wire, gently pull SIR coil wire through steering column. 16. Remove SIR coil assembly from steering column. 17. Reverse procedure to install, noting the following: a. Ensure wheels are in the straight ahead position. b. Ensure coil assembly is in the centered position. c. After completing installation, rearm system as described in Air Bag System Disarming & Arming. d. Turn ignition switch to On position and verify that the AIR BAG or SIR warning lamp flashes seven to nine times and then turns off. If lamp does not respond as specified, refer to System Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations LH Radiator Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations > Page 8253 Discriminating Sensors and Arming Sensors: Description and Operation DESCRIPTION The discriminating and arming sensors are used by the SIR system to determine whether or not certain frontal crashes require deployment of the air bags. OPERATION The sensor consists of a sensing element, normally open switch contacts and a diagnostic resistor. The sensing element closes the switch contacts when the vehicle velocity changes are severe enough to warrant air bag deployment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations > Page 8254 Discriminating Sensors and Arming Sensors: Service and Repair WARNING: The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. LEFT SENSOR 1. Disarm system as described in Air Bag System Disarming & Arming 2. Remove Connector Position Assurance (CPA), then disconnect sensor electrical connector. 3. Remove sensor mounting bolts, then the sensor. 4. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition key to the On position and verify the AIR BAG or SIR warning lamp flashes seven to nine times, then turns off. If warning lamp does not operate as specified, refer to Testing & Inspection. RIGHT SENSOR 1. Disarm system as described in Air Bag System Disarming & Arming. 2. Remove battery, then the Connector Position Assurance (CPA). 3. Disconnect sensor electrical connector. 4. Remove sensor mounting bolts, then the sensor. 5. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition key to the On position and verify the AIR BAG or SIR warning lamp flashes seven to nine times, then turns off. If warning lamp does not operate as specified, refer to System Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Seat Occupant Sensor > Component Information > Technical Service Bulletins > Restraints - Passenger Presence System Information Seat Occupant Sensor: Technical Service Bulletins Restraints - Passenger Presence System Information INFORMATION Bulletin No.: 06-08-50-009F Date: December 23, 2010 Subject: Information on Passenger Presence Sensing System (PPS or PSS) Concerns With Custom Upholstery, Accessory Seat Heaters or Other Comfort Enhancing Devices Models: 2011 and Prior GM Passenger Cars and Trucks Equipped with Passenger Presence Sensing System Supercede: This bulletin is being revised to update the model years. Please discard Corporate Bulletin Number 06-08-50-009E (Section 08 - Body and Accessories). Concerns About Safety and Alterations to the Front Passenger Seat Important ON A GM VEHICLE EQUIPPED WITH A PASSENGER SENSING SYSTEM, USE THE SEAT COVERS AND OTHER SEAT-RELATED EQUIPMENT AS RELEASED BY GM FOR THAT VEHICLE. DO NOT ALTER THE SEAT COVERS OR SEAT-RELATED EQUIPMENT. ANY ALTERATIONS TO SEAT COVERS OR GM ACCESSORIES DEFEATS THE INTENDED DESIGN OF THE SYSTEM. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER SEAT ALTERATIONS, INCLUDING ANY WARRANTY REPAIRS INCURRED. The front passenger seat in many GM vehicles is equipped with a passenger sensing system that will turn off the right front passenger's frontal airbag under certain conditions, such as when an infant or child seat is present. In some vehicles, the passenger sensing system will also turn off the right front passenger's seat mounted side impact airbag. For the system to function properly, sensors are used in the seat to detect the presence of a properly-seated occupant. The passenger sensing system may not operate properly if the original seat trim is replaced (1) by non-GM covers, upholstery or trim, or (2) by GM covers, upholstery or trim designed for a different vehicle or (3) by GM covers, upholstery or trim that has been altered by a trim shop, or (4) if any object, such as an aftermarket seat heater or a comfort enhancing pad or device is installed under the seat fabric or between the occupant and the seat fabric. Aftermarket Seat Heaters, Custom Upholstery, and Comfort Enhancing Pads or Devices Important ON A GM VEHICLE EQUIPPED WITH A PASSENGER SENSING SYSTEM, USE ONLY SEAT COVERS AND OTHER SEAT-RELATED EQUIPMENT RELEASED AS GM ACCESSORIES FOR THAT VEHICLE. DO NOT USE ANY OTHER TYPE OF SEAT COVERS OR SEAT-RELATED EQUIPMENT, OR GM ACCESSORIES RELEASED FOR OTHER VEHICLE APPLICATIONS. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER SEAT ACCESSORIES, INCLUDING ANY WARRANTY REPAIRS MADE NECESSARY BY SUCH USE. Many types of aftermarket accessories are available to customers, upfitting shops, and dealers. Some of these devices sit on top of, or are Velcro(R) strapped to the seat while others such as seat heaters are installed under the seat fabric. Additionally, seat covers made of leather or other materials may have different padding thickness installed that could prevent the Passenger Sensing System from functioning properly. Never alter the vehicle seats. Never add pads or other devices to the seat cushion, as this may interfere with the operation of the Passenger Sensing System and either prevent proper deployment of the passenger airbag or prevent proper suppression of the passenger air bag. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Diagnostic Energy Reserve Module (DERM) <--> [Standby Power Supply, Air Bag] > Component Information > Description and Operation Standby Power Supply: Description and Operation DESCRIPTION The Diagnostic Energy Reserve Module (DERM) performs several system functions. These functions include energy reserve, malfunction detection, malfunction recording, driver notification and frontal crash recording. OPERATION The DERM is connected to the SIR wiring harness by a 24-way connector. This harness connector uses a shorting bar across certain terminals in the contact area. This shorting bar connects the AIR BAG warning lamp to ground when the DERM harness connector is disconnected. This will cause the AIR BAG warning lamp to come on steady whenever the ignition switch is at the Run, Bulb Test or Start positions with the DERM disconnected. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Malfunction Lamp / Indicator, Air Bag > Component Information > Technical Service Bulletins > Customer Interest for Malfunction Lamp / Indicator: > 83-81-34 > Mar > 99 > SIR - Operating Vehicle with Warning Light On Malfunction Lamp / Indicator: Customer Interest SIR - Operating Vehicle with Warning Light On File In Section: 8 - Chassis/Body Electrical Bulletin No.: 83-81-34 Date: March, 1999 INFORMATION Subject: Operating Vehicle with Supplemental Inflatable Restraint (SIR) Warning Light Illuminated Models: 1999 and Prior Passenger Cars and Light Duty Trucks with SDM Controlled Air Bag System The AIR BAG warning light is the key to driver notification of Supplemental Inflatable Restraint (SIR) system malfunctions. When the warning light remains illuminated or continues to flash, one or more of the following conditions may occur if vehicle operation is continued. ^ Non-deployment of the air bags in the event of a crash. ^ Deployment of the air bags without a crash. ^ Deployment of the air bags in crashes less severe than intended. If an AIR BAG warning light is illuminated or flashing, you should advise the customer of these possibilities and that the vehicle should be serviced right away. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Air Bag Systems > Malfunction Lamp / Indicator, Air Bag > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Malfunction Lamp / Indicator: > 83-81-34 > Mar > 99 > SIR - Operating Vehicle with Warning Light On Malfunction Lamp / Indicator: All Technical Service Bulletins SIR - Operating Vehicle with Warning Light On File In Section: 8 - Chassis/Body Electrical Bulletin No.: 83-81-34 Date: March, 1999 INFORMATION Subject: Operating Vehicle with Supplemental Inflatable Restraint (SIR) Warning Light Illuminated Models: 1999 and Prior Passenger Cars and Light Duty Trucks with SDM Controlled Air Bag System The AIR BAG warning light is the key to driver notification of Supplemental Inflatable Restraint (SIR) system malfunctions. When the warning light remains illuminated or continues to flash, one or more of the following conditions may occur if vehicle operation is continued. ^ Non-deployment of the air bags in the event of a crash. ^ Deployment of the air bags without a crash. ^ Deployment of the air bags in crashes less severe than intended. If an AIR BAG warning light is illuminated or flashing, you should advise the customer of these possibilities and that the vehicle should be serviced right away. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Head Restraint System > System Information > Technical Service Bulletins > Restraints - Driver/Passenger Seat Head Rest Information Head Restraint System: Technical Service Bulletins Restraints - Driver/Passenger Seat Head Rest Information INFORMATION Bulletin No.: 10-08-50-003A Date: March 24, 2011 Subject: Information on Driver or Passenger Seat Head Restraint Concerns with Comfort, Custom Upholstery or Other Comfort Enhancing Devices Models: 2012 and Prior GM Passenger Cars and Trucks Equipped with Adjustable Head Restraints Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 10-08-50-003 (Section 08 - Body and Accessories). Important ON A GM VEHICLE EQUIPPED WITH ADJUSTABLE HEAD RESTRAINTS, USE THE HEAD RESTRAINT COVERS, FOAM AND OTHER SEAT-RELATED EQUIPMENT AS RELEASED BY GM FOR THAT VEHICLE. DO NOT ALTER OR REPOSITION THE HEAD RESTRAINT SYSTEM. ANY ALTERATIONS TO HEAD RESTRAINTS DEFEATS THE INTENDED DESIGN OF THE SYSTEM. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER DESIGN ALTERATIONS, INCLUDING ANY WARRANTY REPAIRS INCURRED. You may have a customer with a concern that the head restraint is uncomfortable or sits too far forward. The front driver and passenger seats are equipped with head restraints that have been designed to help minimize injuries while still providing comfort to the occupants. Each GM vehicle has its own specifically designed head restraint. The head restraints should only be used in the vehicle for which they were designed. The head restraint will not operate to its design intent if the original foam is replaced (1) by non-GM foam or head restraint, (2) by GM foam or head restraint designed for a different vehicle, (3) by GM foam or head restraint that has been altered by a trim shop or (4) if any object, such as an aftermarket comfort enhancing pad or device, is installed. Never modify the design of the head restraint or remove the head restraint from the vehicle as this may interfere with the operation of the seating and restraint systems and may prevent proper positioning of the passenger within the vehicle. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Knee Diverter > Component Information > Service and Repair Knee Diverter: Service and Repair WARNING: The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Disarm system as described in Air Bag System Disarming & Arming. 2. Remove lower steering column trim panel. 3. Remove four bolster mounting bolts, then the bolster from instrument panel. 4. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition switch to On position and verify that the AIR BAG or SIR warning lamp flashes seven to nine times and then turns off. If lamp does not respond as specified, refer to System Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > System Component Locations Description Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > System Component Locations > Page 8287 LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > Page 8288 Inflatable Restraint Diagnostic Energy Reserve (With Sensor) Module (SDM) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Relays and Modules - Restraint Systems > Air Bag Control Module > Component Information > Locations > Page 8289 Air Bag Control Module: Description and Operation DESCRIPTION The Sensing and Diagnostic Module (SDM) performs several system functions. These functions include energy reserve, air bag deployment, malfunction detection, malfunction diagnosis, driver notification, frontal crash detection and frontal crash recording. OPERATION The SDM contains a sensing device which converts vehicle velocity changes to an electrical signal. The electrical signal generated is processed by the SDM and then compared to a value stored in memory. When the generated signal exceeds the stored value, additional signals are compared to signals stored in memory. When two of the generated signals exceed the stored values or when one of the generated signals exceeds the stored value and the forward discriminating sensor closes, the SDM will cause current to flow through the inflator modules deploying the air bags. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming Air Bag(s) Arming and Disarming: Service and Repair Air Bag Disarming and Arming Disabling the SIR System The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Ensure front wheels are pointed straight ahead. 2. Turn ignition switch to LOCK position and remove SIR or AIR BAG fuse. 3. Remove Connector Position Assurance (CPA), then disconnect both yellow 2-way SIR electrical connectors at base of steering column. 4. Wait at least 2 minutes before proceeding with diagnosis or service. Enabling the SIR System 1. Connect both 2-way yellow connectors at base of steering column. 2. Install Connector Position Assurance (CPA). 3. Install SIR or AIR BAG fuse into fuse block. 4. Turn ignition to the RUN position and ensure that the "Inflatable Restraint lamp flashes seven to nine times and then turns off. If lamp does not operate as specified, refer to Testing And Inspection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming > Page 8295 Air Bag(s) Arming and Disarming: Service and Repair General Service Precautions CAUTION; When performing service on or around SIR components or SIR wiring, follow the procedures to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Child Restraint > Child Seat Tether Attachment > Component Information > Technical Service Bulletins > Restraints - Child Seat Top Teather Attachment Kits Child Seat Tether Attachment: Technical Service Bulletins Restraints - Child Seat Top Teather Attachment Kits Bulletin No.: 99-09-40-004a Date: April 12, 2005 INFORMATION Subject: Top Tether Hardware Package for Child Restraint Seats Models: 1989-2002 Passenger Cars, Light Duty Trucks and Multi-Purpose Passenger Vehicles (Except EV1 and Prizm) Supercede: This bulletin is being revised to add the 2000-2002 model years. Please discard Corporate Bulletin Number 99-09-40-009 (Section 09 - Restraints). Important: GM of Canada and IPC Dealers are not authorized to utilize this service bulletin. Beginning in August, 1997 General Motors began providing Child Restraint Seat Top Tether Hardware Packages to customers in the United States who requested them. The Top Tether Hardware Package contains the necessary hardware for anchoring a forward facing child restraint seat top tether. One Child Restraint Seat Top Tether Hardware Package will be provided per vehicle to the retail customer at no charge for installation. Charges for installation of additional Top Tether Hardware Packages per vehicle are the responsibility of the customer. Most forward facing child restraint seats (CRS) sold in the United States prior to calendar year 1999 were not sold with top tether straps, but have provisions for them. Top tethers, which are required in Canada, can help to better secure the seat in the vehicle. When a forward facing CRS including a top tether is used, specially designed components must be used to secure the child seat top tether. These components are included in the Hardware Package from GMSPO. Top tethers are not normally required or used with rearward facing infant restraint seats. Rearward facing infant restraint seats should never be secured in the front seat of an air bag equipped vehicle unless the vehicle is equipped with an air bag de-activation (shut-off) switch and the switch has been used to turn the air bag off. Should a retail customer request installation of a Tether Hardware Package at the time of sale or delivery, it is to be installed at no charge to the owner. The labor to install a Tether Hardware Package prior to delivery of a new vehicle to the customer is considered to be part of the delivery "get ready process", and as such, is not claimable. Claiming for the cost and applicable handling allowance of the proper Tether Hardware Package used in the installation is allowed. If the customer requests installation of a Tether Hardware Package some time after delivery, the package is to be provided free of charge. Hardware Packages include installation instructions which are easily followed and can be installed by most customers. However, should the customer request the dealership's assistance to install the Tether Hardware Package, it is to be installed at no charge to the customer and the labor may be claimed. All claims submitted for installation labor of an approved Tether Hardware Package must be supported by a signed customer work order. Additional Hardware Packages and installation charges are the responsibility of the customer. In addition, passenger vehicle deliveries, including vans and sport utilities for daily rental usage, may have one tether hardware package supplied. Additional packages are the owner's responsibility. Dealers may claim appropriate parts under these circumstances. Sufficient quantities of parts should be ordered in advance of the arrival of vehicles to avoid delays. Important: When installing a Child Restraint Seat Top Tether Hardware Package, follow the installation instructions included in the package. Additional information about specific mounting locations and installations may be available in the Seat Belt Section (Sections 9, 10-10, 10-11 or 10A) I of the appropriate Service Manual, or the Restraints section of SI. Any questions regarding this policy should be directed to your Area Manager, Parts or Service. Parts Information For Top Tether Hardware Package part numbers and usage, see Group 14.870 (passenger cars & U-van), or Group 16.710 (Light Duty Truck) of the appropriate GMSPO Parts Catalog. In addition, they can also be found in Accessories Group 21.042. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Child Restraint > Child Seat Tether Attachment > Component Information > Technical Service Bulletins > Restraints - Child Seat Top Teather Attachment Kits > Page 8301 Warranty Information The dealership will be reimbursed for the parts and labor, if applicable, through the submission of a regular warranty claim. All claims submitted must be supported by a signed customer work order. Purchase and installation of additional Hardware Packages is the responsibility of the customer. For Top Tether Hardware Packages installed in the United States, submit as a normal warranty claim using the labor operations and time allowances shown. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Buckle > Component Information > Technical Service Bulletins > Customer Interest for Seat Belt Buckle: > 09-09-40-001A > Feb > 11 > Restraints - Seat Belt Warning Lamp On/Buckling Issues Seat Belt Buckle: Customer Interest Restraints - Seat Belt Warning Lamp On/Buckling Issues INFORMATION Bulletin No.: 09-09-40-001A Date: February 02, 2011 Subject: Seat Belt Buckle Latching Issues and/or Seat Belt Warning Lights Illuminated Models: 2011 and Prior GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7 X Supercede: This bulletin is being revised to add the 2011 model year. Please discard Corporate Bulletin Number 09-09-40-001 (Section 09 - Restraints). This bulletin is being published to advise dealers about seat belt buckles not operating and/or seat belt warning light illumination, as well as difficulty latching and unlatching the buckle or the buckle release button sticking. Analysis of warranty data has determined that this condition may be caused by sticky beverages being spilled onto or into the seat belt buckle assembly. Foreign debris from food, candy wrappers, paper and coins can also contribute to this condition. Important If foreign material (debris) or sticky liquids are the cause of the concern, show the customer the condition of the component (buckle assembly) and explain how it is affecting the function of the restraint system. Strongly recommend that the component be replaced. Point out the fact that this is not a manufacturing defect and is not covered by the new vehicle warranty. If the customer declines to have parts replaced, the service department management must make a notation on the service record that the lack of functionality of seating position with an inoperative buckle was fully explained to the customer. The service department management must advise the customer that having a non-functioning buckle in a seating position voids ability to use that seating position (no one should ride in the seat). Also make the customer aware that it may be against the law to ride in a vehicle without wearing a restraint system. Important Never insert anything other than the seat belt latch plate into the buckle assembly. Do not attempt to dig anything out of a buckle with a tool. Never try to wash out a buckle to remove a spilled liquid as this may damage the buckle. Use the following steps to determine the cause of the concern. 1. Inspect the buckle assembly with a light shining on the latch plate insertion area. Look for any debris or foreign objects in the buckle. 2. If any debris or foreign objects are observed, try to vacuum out the item. After the foreign material is removed, latch and unlatch the seat belt. If the system functions properly, do not replace the seat belt buckle assembly. 3. If the condition has not been corrected, inspect the buckle assembly for any sticky residue. If sticky residue is found, inform the customer that a substance was spilled on the seat belt buckle assembly causing the malfunction. The buckle assembly will need to be replaced at the customer's expense. 4. Refer to SI for seat belt component replacement. Important If foreign material (debris) or sticky liquids are the cause of the concern, show the customer the condition of the component (buckle assembly) and explain how it is affecting the function of the restraint system. Strongly recommend that the component be replaced at the customer's expense. Point out the fact that this is not a manufacturing defect and is not covered by the new vehicle warranty. If the customer declines to have parts replaced, the service department management must make a notation on the service record that the lack of functionality of seating position with an inoperative buckle was fully explained to the customer. The service department management must advise customer that having a non-functioning buckle in a seating position voids ability to use that seating position (no one should ride in the seat). Also make the customer aware that it may be against the law to ride in a vehicle without wearing a restraint system. 5. If further restraint diagnosis is required, refer to Seat Belt System Operational and Functional Checks in SI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Buckle > Component Information > Technical Service Bulletins > Customer Interest for Seat Belt Buckle: > 09-09-40-001A > Feb > 11 > Restraints - Seat Belt Warning Lamp On/Buckling Issues > Page 8310 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Buckle > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Seat Belt Buckle: > 09-09-40-001A > Feb > 11 > Restraints - Seat Belt Warning Lamp On/Buckling Issues Seat Belt Buckle: All Technical Service Bulletins Restraints - Seat Belt Warning Lamp On/Buckling Issues INFORMATION Bulletin No.: 09-09-40-001A Date: February 02, 2011 Subject: Seat Belt Buckle Latching Issues and/or Seat Belt Warning Lights Illuminated Models: 2011 and Prior GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7 X Supercede: This bulletin is being revised to add the 2011 model year. Please discard Corporate Bulletin Number 09-09-40-001 (Section 09 - Restraints). This bulletin is being published to advise dealers about seat belt buckles not operating and/or seat belt warning light illumination, as well as difficulty latching and unlatching the buckle or the buckle release button sticking. Analysis of warranty data has determined that this condition may be caused by sticky beverages being spilled onto or into the seat belt buckle assembly. Foreign debris from food, candy wrappers, paper and coins can also contribute to this condition. Important If foreign material (debris) or sticky liquids are the cause of the concern, show the customer the condition of the component (buckle assembly) and explain how it is affecting the function of the restraint system. Strongly recommend that the component be replaced. Point out the fact that this is not a manufacturing defect and is not covered by the new vehicle warranty. If the customer declines to have parts replaced, the service department management must make a notation on the service record that the lack of functionality of seating position with an inoperative buckle was fully explained to the customer. The service department management must advise the customer that having a non-functioning buckle in a seating position voids ability to use that seating position (no one should ride in the seat). Also make the customer aware that it may be against the law to ride in a vehicle without wearing a restraint system. Important Never insert anything other than the seat belt latch plate into the buckle assembly. Do not attempt to dig anything out of a buckle with a tool. Never try to wash out a buckle to remove a spilled liquid as this may damage the buckle. Use the following steps to determine the cause of the concern. 1. Inspect the buckle assembly with a light shining on the latch plate insertion area. Look for any debris or foreign objects in the buckle. 2. If any debris or foreign objects are observed, try to vacuum out the item. After the foreign material is removed, latch and unlatch the seat belt. If the system functions properly, do not replace the seat belt buckle assembly. 3. If the condition has not been corrected, inspect the buckle assembly for any sticky residue. If sticky residue is found, inform the customer that a substance was spilled on the seat belt buckle assembly causing the malfunction. The buckle assembly will need to be replaced at the customer's expense. 4. Refer to SI for seat belt component replacement. Important If foreign material (debris) or sticky liquids are the cause of the concern, show the customer the condition of the component (buckle assembly) and explain how it is affecting the function of the restraint system. Strongly recommend that the component be replaced at the customer's expense. Point out the fact that this is not a manufacturing defect and is not covered by the new vehicle warranty. If the customer declines to have parts replaced, the service department management must make a notation on the service record that the lack of functionality of seating position with an inoperative buckle was fully explained to the customer. The service department management must advise customer that having a non-functioning buckle in a seating position voids ability to use that seating position (no one should ride in the seat). Also make the customer aware that it may be against the law to ride in a vehicle without wearing a restraint system. 5. If further restraint diagnosis is required, refer to Seat Belt System Operational and Functional Checks in SI. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Buckle > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Seat Belt Buckle: > 09-09-40-001A > Feb > 11 > Restraints - Seat Belt Warning Lamp On/Buckling Issues > Page 8316 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations > Page 8321 Seat Belt Buckle Switch: Connector Locations Cross Car Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations > Page 8322 Cross Car Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Seat Belt Systems > Seat Belt Extension > Component Information > Technical Service Bulletins > Restraints - Extender Availability For Seat Belt Seat Belt Extension: Technical Service Bulletins Restraints - Extender Availability For Seat Belt INFORMATION Bulletin No.: 99-09-40-005F Date: June 23, 2010 Subject: Seat Belt Extender Availability Models: 2011 and Prior GM Passenger Cars and Trucks (Including Saturn) 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add the 2009‐2011 model years and update the Warranty Information. Please discard Corporate Bulletin Number 99-09-40-005E (Section 09 Restraints). Important: DO NOT use belt extenders when securing a child restraint. The seat and shoulder belt restraint systems used in all General Motors vehicles have sufficient belt length to accommodate most drivers and passengers. Consequently, requests for belt extensions (extenders) should be minimal. Seat belt extenders are available ONLY IN BLACK for most GM passenger cars and trucks produced in recent years. They are available in two different lengths, 23 cm (9 in) and 38 cm (15 in). They are designed to be coupled with the existing belts in each vehicle. When in use, the extender makes the belt arrangement a "custom fit" and use by anyone else or in another vehicle will lessen or nullify the protection offered by the vehicle's restraint system. For this reason, it is extremely important that the correct length extender be used for the vehicle and occupant intended. Important: Do not use an extender just to make it easier to buckle the safety belt. Use an extender only when you cannot buckle the safety belt without using an extender. Parts Information For part numbers, usage and availability of extenders, see Extension Kit in Group 14.875 (cars) or Group 16.714 (trucks) of the appropriate parts catalog. Saturn retailers should refer to the appropriate model year Parts & Illustration catalog for the vehicle. U.S. Saab dealers should contact the Parts Help line. Canadian Saab dealers should fax requests to Partech Canada. Warranty Information ^ Seat belt extenders are a NO CHARGE item to all GM customers who request them for their specific vehicles. ^ Dealers should not be charging part costs since these extenders are supplied by GM to the dealers. ^ Dealers should not be charging labor costs since the extender can be customer installed. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Sensors and Switches - Restraint Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations LH Radiator Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Sensors and Switches - Restraint Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations > Page 8331 Discriminating Sensors and Arming Sensors: Description and Operation DESCRIPTION The discriminating and arming sensors are used by the SIR system to determine whether or not certain frontal crashes require deployment of the air bags. OPERATION The sensor consists of a sensing element, normally open switch contacts and a diagnostic resistor. The sensing element closes the switch contacts when the vehicle velocity changes are severe enough to warrant air bag deployment. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Sensors and Switches - Restraint Systems > Discriminating Sensors and Arming Sensors <--> [Impact Sensor] > Component Information > Locations > Page 8332 Discriminating Sensors and Arming Sensors: Service and Repair WARNING: The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. LEFT SENSOR 1. Disarm system as described in Air Bag System Disarming & Arming 2. Remove Connector Position Assurance (CPA), then disconnect sensor electrical connector. 3. Remove sensor mounting bolts, then the sensor. 4. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition key to the On position and verify the AIR BAG or SIR warning lamp flashes seven to nine times, then turns off. If warning lamp does not operate as specified, refer to Testing & Inspection. RIGHT SENSOR 1. Disarm system as described in Air Bag System Disarming & Arming. 2. Remove battery, then the Connector Position Assurance (CPA). 3. Disconnect sensor electrical connector. 4. Remove sensor mounting bolts, then the sensor. 5. Reverse procedure to install, noting the following: a. After completing installation, rearm system as described in Air Bag System Disarming & Arming. b. Turn ignition key to the On position and verify the AIR BAG or SIR warning lamp flashes seven to nine times, then turns off. If warning lamp does not operate as specified, refer to System Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Sensors and Switches - Restraint Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Sensors and Switches - Restraint Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations > Page 8337 Seat Belt Buckle Switch: Connector Locations Cross Car Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Sensors and Switches - Restraint Systems > Seat Belt Buckle Switch > Component Information > Locations > Component Locations > Page 8338 Cross Car Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Restraint Systems > Sensors and Switches - Restraint Systems > Seat Occupant Sensor > Component Information > Technical Service Bulletins > Restraints - Passenger Presence System Information Seat Occupant Sensor: Technical Service Bulletins Restraints - Passenger Presence System Information INFORMATION Bulletin No.: 06-08-50-009F Date: December 23, 2010 Subject: Information on Passenger Presence Sensing System (PPS or PSS) Concerns With Custom Upholstery, Accessory Seat Heaters or Other Comfort Enhancing Devices Models: 2011 and Prior GM Passenger Cars and Trucks Equipped with Passenger Presence Sensing System Supercede: This bulletin is being revised to update the model years. Please discard Corporate Bulletin Number 06-08-50-009E (Section 08 - Body and Accessories). Concerns About Safety and Alterations to the Front Passenger Seat Important ON A GM VEHICLE EQUIPPED WITH A PASSENGER SENSING SYSTEM, USE THE SEAT COVERS AND OTHER SEAT-RELATED EQUIPMENT AS RELEASED BY GM FOR THAT VEHICLE. DO NOT ALTER THE SEAT COVERS OR SEAT-RELATED EQUIPMENT. ANY ALTERATIONS TO SEAT COVERS OR GM ACCESSORIES DEFEATS THE INTENDED DESIGN OF THE SYSTEM. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER SEAT ALTERATIONS, INCLUDING ANY WARRANTY REPAIRS INCURRED. The front passenger seat in many GM vehicles is equipped with a passenger sensing system that will turn off the right front passenger's frontal airbag under certain conditions, such as when an infant or child seat is present. In some vehicles, the passenger sensing system will also turn off the right front passenger's seat mounted side impact airbag. For the system to function properly, sensors are used in the seat to detect the presence of a properly-seated occupant. The passenger sensing system may not operate properly if the original seat trim is replaced (1) by non-GM covers, upholstery or trim, or (2) by GM covers, upholstery or trim designed for a different vehicle or (3) by GM covers, upholstery or trim that has been altered by a trim shop, or (4) if any object, such as an aftermarket seat heater or a comfort enhancing pad or device is installed under the seat fabric or between the occupant and the seat fabric. Aftermarket Seat Heaters, Custom Upholstery, and Comfort Enhancing Pads or Devices Important ON A GM VEHICLE EQUIPPED WITH A PASSENGER SENSING SYSTEM, USE ONLY SEAT COVERS AND OTHER SEAT-RELATED EQUIPMENT RELEASED AS GM ACCESSORIES FOR THAT VEHICLE. DO NOT USE ANY OTHER TYPE OF SEAT COVERS OR SEAT-RELATED EQUIPMENT, OR GM ACCESSORIES RELEASED FOR OTHER VEHICLE APPLICATIONS. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER SEAT ACCESSORIES, INCLUDING ANY WARRANTY REPAIRS MADE NECESSARY BY SUCH USE. Many types of aftermarket accessories are available to customers, upfitting shops, and dealers. Some of these devices sit on top of, or are Velcro(R) strapped to the seat while others such as seat heaters are installed under the seat fabric. Additionally, seat covers made of leather or other materials may have different padding thickness installed that could prevent the Passenger Sensing System from functioning properly. Never alter the vehicle seats. Never add pads or other devices to the seat cushion, as this may interfere with the operation of the Passenger Sensing System and either prevent proper deployment of the passenger airbag or prevent proper suppression of the passenger air bag. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antenna > Antenna Motor > Component Information > Locations RH Rear Side Of Engine Compartment With Radio Power Antenna Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antenna > Antenna Relay > Component Information > Locations > Power Antenna Relay LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antenna > Antenna Relay > Component Information > Locations > Power Antenna Relay > Page 8352 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antenna > Antenna, Radio > Component Information > Locations RH Rear Side Of Engine Compartment With Radio Power Antenna Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Alarm Module, (Vehicle Antitheft) > Component Information > Service and Repair Alarm Module: Service and Repair PROGRAMMING A NEW THEFT DETERRENT MODULE IMPORTANT: Any new PASS-Key II Theft Deterrent Module will automatically program to the resistance of the key (or interrogator setting) being used at the first ignition "ON" cycle. This can only be done once for the life of the module. New modules are unprogrammed. Before the system will function properly after a new module has been installed, it must be programmed to the code that matches the customer1s keys. Programming a new module is very simple: 1. Install the new, unprogrammed module. 2. Insert one of the customer's keys in the ignition lock cylinder and turn it to the "ON" position. It's a good idea to start the Engine at this time to verify system operation. 3. Observe the "PASSKEY" indicator Lamp: ^ The indicator lamp should light for about five seconds and then go out. If the wiring or contacts to the Key Resistance Pellet or the key is defective or intermittent and a new module is installed, the Engine will start but the "PASSKEY" indicator will flash at a rate of one flash per second until the Ignition Switch is turned off. This indicates that the module did not program and that the system components, wiring and contacts should be checked for a fault. IMPORTANT: Before connecting the interrogrator to the ignition lock cylinder circuit, always verify vehicle key code and set the code into the interrogrator using the "key code" knob. This will prevent programming an unprogrammed module with an undesired key code. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Antitheft Relay > Component Information > Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Antitheft Relay > Component Information > Locations > Page 8363 Theft Deterrent Relay Daytime Running Lamps (DRL) Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Ignition Key In Signal, Antitheft > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Programming Connector > Component Information > Locations Keyless Entry Programming Connector: Locations LH Luggage Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Receiver > Component Information > Locations Rear Shelf, Top View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Receiver > Component Information > Locations > Page 8374 Keyless Entry Receiver: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Receiver > Component Information > Locations > Page 8375 C406: Body Harness To Tailgate Harness, Headlamp Automatic Control Module (C1), Remote Control Door Lock Receiver Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Transmitter > Component Information > Technical Service Bulletins > Tools Keyless Entry Transmitter Tester Keyless Entry Transmitter: Technical Service Bulletins Tools - Keyless Entry Transmitter Tester File In Section: 9 - Accessories Bulletin No.: 83-90-12 Date: August, 1998 INFORMATION Subject: Essential Tool J 43241 Remote Keyless Entry and Passive Keyless Entry Transmitter Tester Models: 1990-99 Passenger Cars and Trucks with Remote Keyless Entry or Passive Keyless Entry Systems A new essential tool, J 43241 Remote Keyless Entry Transmitter Tester, has been sent to all GM Dealers. This tester can be used on all RKE and PKE systems, on past as well as current models. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Transmitter > Component Information > Technical Service Bulletins > Tools Keyless Entry Transmitter Tester > Page 8380 Important: Before using the tester and the diagnostic chart, the following two steps must be performed. 1. Verify that the keyless entry transmitter is the correct model for the vehicle remote system. An incorrect model transmitter may pass this test, but may not activate the vehicle remote system. The correct transmitter can usually be identified by part number. 2. Ensure that the transmitter is synchronized with the vehicle (if applicable). Refer to Transmitter Synchronization in the appropriate Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Transmitter > Component Information > Technical Service Bulletins > Page 8381 Keyless Entry Transmitter: Service and Repair 1. Reposition rear compartment trim to access the programming connector located at the left of the rear compartment, for sedan. 2. Remove right back body pillar finish panel to access programming connector, for wagon. 3. Ground the programming connector by connecting the terminals together. ^ The system will verify this has occurred by performing a lock all, unlock drivers door/unlock all, and trunk/endgate cycle. 4. Press any key on either transmitter. ^ This step programs that particular transmitter to the receiver. ^ The system will verify by performing the same lock/unlock, lock/unlock cycle. 5. The Automatic Door Locking/Unlocking function is automatically enabled for this transmitter. To leave it enabled, skip to step 6. To disable the Automatic Door Locking/Unlocking function for this transmitter, perform the following sequence 3 times. A. Press the door lock button within 1 second of step C the 2nd and 3rd time through this sequence. B. Press the door unlock button within 1 second of step A. C Press the trunk button within 1 second of step B. ^ The receiver will cycle through the lock, unlock, trunk sequence 3 times as verification. 6. To program a second transmitter to the receiver, repeat step 4 with the second transmitter. Otherwise, go to 7. 7. Disconnect the programming connector. ^ System will not operate if ground connection is not removed. 8. Verify operation of each transmitter. 9. Reposition rear compartment trim, for sedan. 10. Install right back body pillar finish panel, for wagon. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Antitheft and Alarm Systems > Security Lamp/Indicator > Component Information > Description and Operation Security Lamp/Indicator: Description and Operation The security indicator is controlled by the theft deterrent module. The module will turn the SECURITY lamp on for about five seconds during engine start-up for a bulb check. A solid (not flashing) SECURITY indicator is illuminated if the theft deterrent module enters shut down mode thus preventing the vehicle from starting. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Technical Service Bulletins > Radio Telephone/Mobile Radio - Install/Troubleshooting Technical Service Bulletin # 83-96-05 Date: 980701 Radio Telephone/Mobile Radio - Install/Troubleshooting File In Section: 9 - Accessories Bulletin No.: 83-96-05 Date: July, 1998 Subject: Radio Telephone/Mobile Radio (Transceiver) Installation and Troubleshooting Guidelines Models: 1990-99 Passenger Cars and Trucks This bulletin cancels and supercedes bulletin 34-92-12. Please discard Corporate Bulletin Number 34-92-12 (Section 9 - Accessories). The following information is being provided to assist in the installation and troubleshooting of Radio Telephone/Mobile Radios. Certain radio telephones or land mobile radios (also known as Radio Transceivers), or the way in which they are installed, may adversely affect various vehicle operations such as engine performance, driver information, entertainment and electrical systems. Expenses incurred to protect the vehicle systems from any adverse effect of any such installation are NOT the responsibility of General Motors Corporation. The following are general guidelines for installing a radio transceiver in General Motors vehicles. These guidelines are intended to supplement, but not to be used in place of, detailed instructions which are the sole responsibility of the manufacturer of the involved radio transceiver. Although this document refers to passenger vehicles, the same general guidelines apply to trucks. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Technical Service Bulletins > Radio Telephone/Mobile Radio - Install/Troubleshooting > Page 8389 EMC TROUBLESHOOTING CHART 1. Transceiver Location Refer to the attached figures during installation. 1. Transceiver Location Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Technical Service Bulletins > Radio Telephone/Mobile Radio - Install/Troubleshooting > Page 8390 a. One piece transceivers should be mounted under the dash, or on the transmission hump where they will not interfere with vehicle controls or passenger movement (See Figure 1 - One Piece Transceiver Installation). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Technical Service Bulletins > Radio Telephone/Mobile Radio - Install/Troubleshooting > Page 8391 b. Locate the transceiver for remote radios on the driver's side of trunk as near to the vehicle body side as possible (See Figure 2 - Trunk Mount Transceiver Installation). Caution: To avoid possible serious injury, do not mount any transceivers, microphones, speakers, or any other item In the deployment path of a Supplemental Inflatable Restraint (SIR) or "Air Bag". 2. Antenna Installation a. Each vehicle model reacts to radio frequency energy differently. It is suggested that a magnetic-mount antenna be used to check the proposed antenna location for unwanted effects on the vehicle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Technical Service Bulletins > Radio Telephone/Mobile Radio - Install/Troubleshooting > Page 8392 Antenna location is a major factor in these effects. b. The antenna should be a permanent-mount type, located in the center of the roof or center of the rear deck lid. If a magnet-mount antenna is used, care should be taken to mount the antenna in the same location as a permanent-mount type. If a disguise-mount antenna is used, great care should be taken to shield (using copper tape, etc.) any tuning network from vehicle electronics and wiring, or mount the tuning network in an area completely clear (6 inches or 15 cm away) of vehicle electronics and wiring. c. Standard metal mount antennas may be mounted on a vehicle with non-metallic body panels by two methods: 1. Mount the antenna near a metal frame section and bond the antenna mount to the frame with a short metal strap, which will provide the ground plane connection. 2. Some antenna manufacturers may offer "Ground Plane Kits" that consist of self adhesive metal foil that may be attached to the body panel to provide a ground plane connection. d. Glass Mount Antennas Glass mounted antennas should be kept as high as possible in the center of the rear window or windshield, between rear window defrost "grid lines", if present. Some vehicles use glass that contains a thin metallic layer for defrosting, or to control solar gain. GLASS MOUNT ANTENNAS WILL NOT FUNCTION WHEN MOUNTED ON THIS TYPE OF GLASS. 3. Antenna Cable Routing a. Always use high quality coax cable (95% shield coverage minimum), located away (at least 6 inches or 15 cm) from ECM's, PCM's and other electronic modules. b. Care should be taken to maintain as great a distance as possible between any vehicle wiring and coax cable. 4. Antenna Tuning It is important that the antenna be tuned properly and that reflected power be kept to less than 10% (VSWR less than 2:1) at all operating frequencies. Important: High VSWR has been shown to contribute/cause interference problems with vehicle systems. 5. Radio Wiring and Power Lead Connection Locations a. Methods to connect radio power on General Motors vehicles is dependent on the vehicle model (See Figure 1 - One Piece Transceiver Installation or Figure 2 - Trunk Mount Transceiver Installation as needed). Do not connect the negative power lead to any under-dash termination point. One of the following four methods is suggested: 1. Connect the positive and negative power leads directly to the battery terminals. GM approved methods of connecting auxiliary wiring include the adapter package illustrated in Figure 4 - Power Cable Battery Connections. Important: It is recommended that a fuse be placed in the transceiver negative power lead. This is to prevent possible transceiver damage in the event the battery to engine block ground lead is inadvertently disconnected. 2. Connect the positive lead to the auxiliary power terminal (usually identified by a red plastic cover in the underhood area). Connect the negative lead directly to the negative battery terminal. Important: See above important statement regarding fusing the negative power lead. 3. Connect the positive lead to the auxiliary power terminal (usually identified by a red plastic cover in the underhood area). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Technical Service Bulletins > Radio Telephone/Mobile Radio - Install/Troubleshooting > Page 8393 Connect the negative lead to the battery body connection point (usually identified by a short # 10 AWG or larger wire running from the negative battery terminal to the body of the vehicle). Important: See above important statement regarding fusing the negative power lead. 4. Connect the positive and negative leads to the Special Equipment Option (SEO) wiring provided for this purpose (if vehicle has this option). b. For One Piece Transceivers (See Figure 1 - One Piece Transceiver Installation) When ignition switch control is desired, and no SEO wiring exists, a 12 volt power contactor must be installed in the transceiver positive power lead (See Figure 3 - Power Contactor Wiring). The contactor (supplied by the installer) should be located near a proper 12 volt feed source. One lead of the contactor coil should be connected through an appropriate in-line fuse to an available accessory circuit or ignition circuit not Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Technical Service Bulletins > Radio Telephone/Mobile Radio - Install/Troubleshooting > Page 8394 powered during engine cranking. The return lead of the contactor coil must return to a proper fused negative point. c. Handset or Control Units 1. Any negative power lead from a handset or control unit must return to a properly fused negative connection point. 2. It is preferable that the positive power lead for a handset, or control unit, be connected directly to a properly fused positive power feed point. If ignition switch control is desired, the handset or control unit positive power lead may be connected through an appropriate in-line fuse to an available accessory circuit (or ignition circuit not powered during engine cranking). 3. It is recommended that the handset or control unit positive and negative power leads be appropriately fused separately from the transceiver positive and negative power leads. d. Multiple Transceivers or Receivers If multiple transceivers or receivers are to be installed in the vehicle, power leads to the trunk or under the dash should be connected to covered, insulated terminal strips. All transceivers or receivers may then have their power leads connected to the insulated terminal strips. This makes a neater installation and reduces the number of wires running to the vehicle underhood area. Both positive and negative power leads should be fused. 6. Radio Wire Routing (See Figure 1 - One Piece Transceiver Installation, or Figure 2 - Trunk Mount Transceiver Installation as needed). a. The power leads (fused) should be brought through a grommeted hole (provided by the installer) in the front cowl. For trunk mounted transceivers, the cables should continue on along the driver's side door sills, under the rear seat and into the trunk through a rear bulkhead. Maintain as great a distance as possible between radio power leads and vehicle electronic modules and wiring. b. If the radio power leads need to cross the engine compartment, they should cross between the engine and the front of the vehicle. Troubleshooting Refer to the Troubleshooting Chart as needed. 1. Most vehicle-radio interaction is avoided by following the Installation Guidelines outlined above. 2. If vehicle-radio interaction is evident following radio installation, the source of the problem should be determined prior to further vehicle/radio operation. The EMC Troubleshooting Chart should help in determining the source of the vehicle-radio interaction. Parts Information P/N Description 1846855 Adapter Kit, Side Terminal Battery (consisting of Adapter Terminal, Terminal Cover, Wire Connector, Insulation Boot) 12004188 Bolt, Battery Cable Terminal 12354951 Spacer, Battery Cable Terminal Parts are currently available from GMSPO. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Locations > Cellular Mobile Telephone Microphone Connector (UV8) Front Headliner Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Locations > Cellular Mobile Telephone Microphone Connector (UV8) > Page 8397 RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Locations > Cellular Mobile Telephone Microphone Connector (UV8) > Page 8398 RH Luggage Compartment (UV8) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions Cellular Phone: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8401 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8402 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8403 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8404 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8405 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8406 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8407 Cellular Phone: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8408 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8409 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8410 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8411 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8412 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8413 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8414 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8415 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8416 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8417 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8418 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8419 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8420 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8421 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8422 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8423 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8424 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8425 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8426 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8427 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8428 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8429 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8430 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8431 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8432 Cellular Phone: Electrical Diagrams Cellular Mobile Telephone (Part 1 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Cellular Phone > Component Information > Diagrams > Diagram Information and Instructions > Page 8433 Cellular Mobile Telephone (Part 2 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Emergency Contact Module > Component Information > Technical Service Bulletins > OnStar(R) - Aftermarket Device Interference Information Emergency Contact Module: Technical Service Bulletins OnStar(R) - Aftermarket Device Interference Information INFORMATION Bulletin No.: 08-08-46-004 Date: August 14, 2008 Subject: Information on Aftermarket Device Interference with OnStar(R) Diagnostic Services Models: 2009 and Prior GM Passenger Car and Truck (including Saturn) 2009 and Prior HUMMER H2, H3 Models 2009 and Prior Saab 9-7X with OnStar(R) (RPO UE1) This bulletin is being issued to provide dealer service personnel with information regarding aftermarket devices connected to the Diagnostic Link Connector (DLC) and the impact to OnStar(R) diagnostic probes and Vehicle Diagnostic e-mails. Certain aftermarket devices, when connected to the Diagnostic Link Connector, such as, but not limited to, Scan Tools, Trip Computers, Fuel Economy Analyzers and Insurance Tracking Devices, interfere with OnStar's ability to perform a diagnostic probe when requested (via a blue button call) by a subscriber. These devices also prohibit the ability to gather diagnostic and tire pressure data for a subscriber's scheduled OnStar(R) Vehicle Diagnostic (OVD) e-mail. These aftermarket devices utilize the Vehicles serial data bus to perform data requests and/or information gathering. When these devices are requesting data, OnStar(R) is designed not to interfere with any data request being made by these devices as required by OBD II regulations. The OnStar(R) advisor is unable to definitively detect the presence of these devices and will only be able to inform the caller or requester of the unsuccessful or incomplete probe and may in some cases refer the subscriber/requester to take the vehicle to a dealer for diagnosis of the concern. When performing a diagnostic check for an unsuccessful or incomplete OnStar(R) diagnostic probe, or for concerns regarding completeness of the OnStar(R) Vehicle Diagnostic (OVD) e-mail, verify that an aftermarket device was not present at the time of the requested probe. Regarding the OVD e-mail, if an aftermarket device is interfering (including a Scan Tool of any type), the e-mail will consistently display a "yellow" indication in diagnostics section for all vehicle systems except the OnStar(R) System and Tire Pressure data (not available on all vehicles) will not be displayed (i.e. section is collapsed). Successful diagnostic probes and complete OVD e-mails will resume following the removal or disconnecting of the off-board device. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Global Positioning System > Component Information > Technical Service Bulletins > OnStar(R) - Aftermarket Device Interference Information Global Positioning System: Technical Service Bulletins OnStar(R) - Aftermarket Device Interference Information INFORMATION Bulletin No.: 08-08-46-004 Date: August 14, 2008 Subject: Information on Aftermarket Device Interference with OnStar(R) Diagnostic Services Models: 2009 and Prior GM Passenger Car and Truck (including Saturn) 2009 and Prior HUMMER H2, H3 Models 2009 and Prior Saab 9-7X with OnStar(R) (RPO UE1) This bulletin is being issued to provide dealer service personnel with information regarding aftermarket devices connected to the Diagnostic Link Connector (DLC) and the impact to OnStar(R) diagnostic probes and Vehicle Diagnostic e-mails. Certain aftermarket devices, when connected to the Diagnostic Link Connector, such as, but not limited to, Scan Tools, Trip Computers, Fuel Economy Analyzers and Insurance Tracking Devices, interfere with OnStar's ability to perform a diagnostic probe when requested (via a blue button call) by a subscriber. These devices also prohibit the ability to gather diagnostic and tire pressure data for a subscriber's scheduled OnStar(R) Vehicle Diagnostic (OVD) e-mail. These aftermarket devices utilize the Vehicles serial data bus to perform data requests and/or information gathering. When these devices are requesting data, OnStar(R) is designed not to interfere with any data request being made by these devices as required by OBD II regulations. The OnStar(R) advisor is unable to definitively detect the presence of these devices and will only be able to inform the caller or requester of the unsuccessful or incomplete probe and may in some cases refer the subscriber/requester to take the vehicle to a dealer for diagnosis of the concern. When performing a diagnostic check for an unsuccessful or incomplete OnStar(R) diagnostic probe, or for concerns regarding completeness of the OnStar(R) Vehicle Diagnostic (OVD) e-mail, verify that an aftermarket device was not present at the time of the requested probe. Regarding the OVD e-mail, if an aftermarket device is interfering (including a Scan Tool of any type), the e-mail will consistently display a "yellow" indication in diagnostics section for all vehicle systems except the OnStar(R) System and Tire Pressure data (not available on all vehicles) will not be displayed (i.e. section is collapsed). Successful diagnostic probes and complete OVD e-mails will resume following the removal or disconnecting of the off-board device. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Memory Positioning Systems > Memory Positioning Module > Component Information > Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Memory Positioning Systems > Seat Memory Switch > Component Information > Locations Seat Memory Switch: Locations LH Front door on armrest Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Navigation System > Component Information > Technical Service Bulletins > OnStar(R) - Aftermarket Device Interference Information Navigation System: Technical Service Bulletins OnStar(R) - Aftermarket Device Interference Information INFORMATION Bulletin No.: 08-08-46-004 Date: August 14, 2008 Subject: Information on Aftermarket Device Interference with OnStar(R) Diagnostic Services Models: 2009 and Prior GM Passenger Car and Truck (including Saturn) 2009 and Prior HUMMER H2, H3 Models 2009 and Prior Saab 9-7X with OnStar(R) (RPO UE1) This bulletin is being issued to provide dealer service personnel with information regarding aftermarket devices connected to the Diagnostic Link Connector (DLC) and the impact to OnStar(R) diagnostic probes and Vehicle Diagnostic e-mails. Certain aftermarket devices, when connected to the Diagnostic Link Connector, such as, but not limited to, Scan Tools, Trip Computers, Fuel Economy Analyzers and Insurance Tracking Devices, interfere with OnStar's ability to perform a diagnostic probe when requested (via a blue button call) by a subscriber. These devices also prohibit the ability to gather diagnostic and tire pressure data for a subscriber's scheduled OnStar(R) Vehicle Diagnostic (OVD) e-mail. These aftermarket devices utilize the Vehicles serial data bus to perform data requests and/or information gathering. When these devices are requesting data, OnStar(R) is designed not to interfere with any data request being made by these devices as required by OBD II regulations. The OnStar(R) advisor is unable to definitively detect the presence of these devices and will only be able to inform the caller or requester of the unsuccessful or incomplete probe and may in some cases refer the subscriber/requester to take the vehicle to a dealer for diagnosis of the concern. When performing a diagnostic check for an unsuccessful or incomplete OnStar(R) diagnostic probe, or for concerns regarding completeness of the OnStar(R) Vehicle Diagnostic (OVD) e-mail, verify that an aftermarket device was not present at the time of the requested probe. Regarding the OVD e-mail, if an aftermarket device is interfering (including a Scan Tool of any type), the e-mail will consistently display a "yellow" indication in diagnostics section for all vehicle systems except the OnStar(R) System and Tire Pressure data (not available on all vehicles) will not be displayed (i.e. section is collapsed). Successful diagnostic probes and complete OVD e-mails will resume following the removal or disconnecting of the off-board device. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Compact Disc Player (CD) > Component Information > Technical Service Bulletins > Customer Interest for Compact Disc Player (CD): > 649601 > Jan > 97 > Compact Disc Players - CD Changer Loading Procedures Compact Disc Player (CD): Customer Interest Compact Disc Players - CD Changer Loading Procedures File In Section: 9 - Accessories Bulletin No.: 64-96-01 Date: January, 1997 INFORMATION Subject: Compact Disc Players - Procedures for Correct Use and Maintenance Models: 1997 and Prior Passenger Cars and Trucks CD Changer Loading Procedures Because of differences in CD changer loading procedures, some confusion exists regarding this issue. Although correct loading procedures are included with each changer's Owner's Manual, often this information is not available to the dealer service personnel. Verify proper loading when evaluating customer concerns of "CD inoperative". Delco Electronics Product Type Loading Procedure Radio w/intergral CD label side up 6 disc changer (LLAI) label side up 10 disc changer (FMI) label side up 12 disc changer (LLAI) label side down Important: Failure to load magazine/player correctly will disable the operation. Important: Only the 12 disc changer is to be loaded with the label side down. CD Cleaners Avoid use of commercially available CD cleaners. The use of CD cleaners is not recommended and can damage the player's CD mechanism. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Compact Disc Player (CD) > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Compact Disc Player (CD): > 649601 > Jan > 97 > Compact Disc Players - CD Changer Loading Procedures Compact Disc Player (CD): All Technical Service Bulletins Compact Disc Players - CD Changer Loading Procedures File In Section: 9 - Accessories Bulletin No.: 64-96-01 Date: January, 1997 INFORMATION Subject: Compact Disc Players - Procedures for Correct Use and Maintenance Models: 1997 and Prior Passenger Cars and Trucks CD Changer Loading Procedures Because of differences in CD changer loading procedures, some confusion exists regarding this issue. Although correct loading procedures are included with each changer's Owner's Manual, often this information is not available to the dealer service personnel. Verify proper loading when evaluating customer concerns of "CD inoperative". Delco Electronics Product Type Loading Procedure Radio w/intergral CD label side up 6 disc changer (LLAI) label side up 10 disc changer (FMI) label side up 12 disc changer (LLAI) label side down Important: Failure to load magazine/player correctly will disable the operation. Important: Only the 12 disc changer is to be loaded with the label side down. CD Cleaners Avoid use of commercially available CD cleaners. The use of CD cleaners is not recommended and can damage the player's CD mechanism. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns Radio/Stereo: Technical Service Bulletins Audio - Procedure To Handle Customer Radio Concerns File In Section: 9 - Accessories Bulletin No.: 68-96-O1A Date: October, 1996 INFORMATION Subject: Procedure to Handle Customer Radio Concerns Models: 1997 and Prior Passenger Cars and Trucks This bulletin is being revised to change the Sales Center Information to Service Center Information. Please discard Corporate Bulletin Number 68-96-01 (Section 9 - Accessories). Many of the radios being returned to the Delco Electronics remanufacturing centers have been misdiagnosed. This misdiagnosis results in unnecessary customer comebacks, decreased customer satisfaction and reduces the availability of exchange radios. To resolve these issues, the following information was developed to give General Motors' dealers a common service process to handle customer audio system concerns. When a customer either calls or comes in with a concern about the radio system in their vehicle, it is important that as much information as possible is gathered. This process begins with the Service Consultant asking the customer specific questions related to their vehicle as outlined on the Service Writer/Customer Check list. Once the Service Consultant has completed the diagnostic worksheet, it should be attached to the customer repair order for the technician. This worksheet should help the technician determine if the concern is vehicle related or radio related. Two excellent service manuals are also available for this purpose and are available from General Motors at the address shown below. A service bulletin, 34-92-12, Radio Frequency Interference Diagnosis, is also available as is assistance from the Divisional Technical Assistance Centers. Mascotech Mktg. Service 1972 Brown Road Auburn Hills, ML 48326 1-800-393-4831 Delco Electronics Sound Service Audio Systems Diagnostic Guide P/N 19007.03-1A @ $10.00 per manual STG Audio Systems Training manual P/N 19007.03-2 @ $15.00 per manual Repairs to the vehicle or the audio system can usually be done very quickly and the vehicle returned to the customer that day. If the diagnosis indicates that the radio needs to be replaced, remove the radio from the vehicle and order an exchange radio from your local AC Delco radio exchange center. There are 28 approved AC Delco exchange centers nationally (listing attached). If your local exchange center does not have the required exchange radio, it is important that you contact the AC Delco locator service. This service can be found on the Service Parts TRACS system 1-800-433-6961, prompt 4. It will be necessary to request overnight shipping so that the owner's vehicle is retained at your dealership for only one night. If the vehicle is kept overnight and it is a warranty repair, the customer should be offered courtesy transportation or alternate transportation. Please do not return the vehicle with the suspect radio installed or without a radio. Many of our vehicles today use a multiplex wiring system and the vehicle will not run correctly without a radio. When you receive the exchange radio, please return the removed radio to the AC Delco Exchange Center within 24 hours (please enclose the diagnostic worksheet that the Service Consultant and the Technician used with the removed radio along with the 1078 form). This will help the AC Delco Exchange Center. In the event you know the vehicle will need a radio before the customer brings the vehicle in, every effort should be made to have a pre-exchanged radio available. A radio identification list is attached to help you select the correct radio. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8471 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8472 AC Delco AUTHORIZED ELECTRONIC SERVICE CENTERS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8473 Duplicate form for your convenience SERVICE WRITER/CUSTOMER CHECK LIST Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8474 RECEPTION/NOISE CONCERN: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8475 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8476 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8477 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8478 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8479 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8480 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Audio - Procedure To Handle Customer Radio Concerns > Page 8481 1997 APPLICATIONS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Page 8482 Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Page 8483 Radio/Stereo: Diagrams Radio Receiver: C1 Radio Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Page 8484 Radio: C1 And C2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Radio/Stereo > Component Information > Technical Service Bulletins > Page 8485 Radio/Stereo: Service and Repair When installing radio, be sure to adjust antenna trimmer for peak reception. Also, be sure to connect speaker before applying power to radio. 1. Disconnect battery ground cable. 2. Remove steering column lower trim panel, then remove lefthand trim panel. 3. Remove radio bracket to instrument carrier attaching screws, then pull radio and bracket assembly outward. 4. Disconnect radio and antenna electrical connectors. 5. Remove radio to bracket attaching nuts, then remove radio. 6. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Speaker > Component Information > Locations > Component Locations Speaker: Component Locations LH LH Side of rear shelf RH RH Side of rear shelf Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Speaker > Component Information > Locations > Component Locations > Page 8490 Speaker: Connector Locations RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Radio, Stereo, and Compact Disc > Speaker > Component Information > Locations > Component Locations > Page 8491 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Alarm Module, (Vehicle Antitheft) > Component Information > Service and Repair Alarm Module: Service and Repair PROGRAMMING A NEW THEFT DETERRENT MODULE IMPORTANT: Any new PASS-Key II Theft Deterrent Module will automatically program to the resistance of the key (or interrogator setting) being used at the first ignition "ON" cycle. This can only be done once for the life of the module. New modules are unprogrammed. Before the system will function properly after a new module has been installed, it must be programmed to the code that matches the customer1s keys. Programming a new module is very simple: 1. Install the new, unprogrammed module. 2. Insert one of the customer's keys in the ignition lock cylinder and turn it to the "ON" position. It's a good idea to start the Engine at this time to verify system operation. 3. Observe the "PASSKEY" indicator Lamp: ^ The indicator lamp should light for about five seconds and then go out. If the wiring or contacts to the Key Resistance Pellet or the key is defective or intermittent and a new module is installed, the Engine will start but the "PASSKEY" indicator will flash at a rate of one flash per second until the Ignition Switch is turned off. This indicates that the module did not program and that the system components, wiring and contacts should be checked for a fault. IMPORTANT: Before connecting the interrogrator to the ignition lock cylinder circuit, always verify vehicle key code and set the code into the interrogrator using the "key code" knob. This will prevent programming an unprogrammed module with an undesired key code. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Antenna Relay > Component Information > Locations > Power Antenna Relay LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Antenna Relay > Component Information > Locations > Power Antenna Relay > Page 8500 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Antitheft Relay > Component Information > Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Antitheft Relay > Component Information > Locations > Page 8504 Theft Deterrent Relay Daytime Running Lamps (DRL) Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Emergency Contact Module > Component Information > Technical Service Bulletins > OnStar(R) - Aftermarket Device Interference Information Emergency Contact Module: Technical Service Bulletins OnStar(R) - Aftermarket Device Interference Information INFORMATION Bulletin No.: 08-08-46-004 Date: August 14, 2008 Subject: Information on Aftermarket Device Interference with OnStar(R) Diagnostic Services Models: 2009 and Prior GM Passenger Car and Truck (including Saturn) 2009 and Prior HUMMER H2, H3 Models 2009 and Prior Saab 9-7X with OnStar(R) (RPO UE1) This bulletin is being issued to provide dealer service personnel with information regarding aftermarket devices connected to the Diagnostic Link Connector (DLC) and the impact to OnStar(R) diagnostic probes and Vehicle Diagnostic e-mails. Certain aftermarket devices, when connected to the Diagnostic Link Connector, such as, but not limited to, Scan Tools, Trip Computers, Fuel Economy Analyzers and Insurance Tracking Devices, interfere with OnStar's ability to perform a diagnostic probe when requested (via a blue button call) by a subscriber. These devices also prohibit the ability to gather diagnostic and tire pressure data for a subscriber's scheduled OnStar(R) Vehicle Diagnostic (OVD) e-mail. These aftermarket devices utilize the Vehicles serial data bus to perform data requests and/or information gathering. When these devices are requesting data, OnStar(R) is designed not to interfere with any data request being made by these devices as required by OBD II regulations. The OnStar(R) advisor is unable to definitively detect the presence of these devices and will only be able to inform the caller or requester of the unsuccessful or incomplete probe and may in some cases refer the subscriber/requester to take the vehicle to a dealer for diagnosis of the concern. When performing a diagnostic check for an unsuccessful or incomplete OnStar(R) diagnostic probe, or for concerns regarding completeness of the OnStar(R) Vehicle Diagnostic (OVD) e-mail, verify that an aftermarket device was not present at the time of the requested probe. Regarding the OVD e-mail, if an aftermarket device is interfering (including a Scan Tool of any type), the e-mail will consistently display a "yellow" indication in diagnostics section for all vehicle systems except the OnStar(R) System and Tire Pressure data (not available on all vehicles) will not be displayed (i.e. section is collapsed). Successful diagnostic probes and complete OVD e-mails will resume following the removal or disconnecting of the off-board device. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Relay Module: Customer Interest Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8517 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8518 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8519 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Relay Module: All Technical Service Bulletins Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8525 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8526 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relays and Modules - Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8527 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Relay Module: Customer Interest Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8536 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8537 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > Customer Interest for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8538 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical MIL ON/DTC's Set By Various Control Modules Relay Module: All Technical Service Bulletins Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical MIL ON/DTC's Set By Various Control Modules > Page 8544 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical MIL ON/DTC's Set By Various Control Modules > Page 8545 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Accessories and Optional Equipment > Relay Module > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Relay Module: > 09-06-03-004D > Dec > 10 > Electrical MIL ON/DTC's Set By Various Control Modules > Page 8546 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Bumper > Front Bumper > Front Bumper Cover / Fascia > System Information > Technical Service Bulletins > Body - TPO Fascia Cleaning Prior to Painting Front Bumper Cover / Fascia: Technical Service Bulletins Body - TPO Fascia Cleaning Prior to Painting INFORMATION Bulletin No.: 08-08-51-002 Date: March 12, 2008 Subject: New Primer For TPO Fascias and Affected Cleaning Process of Painting Operation Models: 2009 and Prior Passenger Cars and Trucks 2009 and Prior HUMMER H2, H3 The purpose of this bulletin is to inform the technician that General Motors has made a change in the primer it uses for TPO plastic for service parts. This new primer comes in several different colors from five different suppliers. This change affects the cleaning process of the painting operation. The new process is as follows. 1. Wash with soap and water. 2. Clean with a 50% mix of isopropyl alcohol and water (or a waterborne cleaner). Check with your paint supplier for product recommendations. 3. Scuff sand per your paint suppliers recommendations. Note: The use of a solvent-type cleaner will soften, or begin to dissolve the primer. Base coats do not have any affect on this primer. 4. Reclean with a 50% mix of isopropyl alcohol and water (or a waterborne cleaner). All fascias, with the exception of the Corvette, Camaro, and Cadillac XLR, are made of TPO. You may find other TPO parts with this primer. If the technician has a question as to the type of plastic they are painting, inspect the back of the part for the plastic symbol (TPO). Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Bumper > Front Bumper > Front Bumper Reinforcement > System Information > Technical Service Bulletins > Body - Polypropylene Energy Absorber Replacement Front Bumper Reinforcement: Technical Service Bulletins Body - Polypropylene Energy Absorber Replacement Bulletin No.: 07-08-63-001 Date: April 17, 2007 INFORMATION Subject: Information on Repair of Polypropylene Energy Absorbers Models: 2007 and Prior GM Passenger Cars and Trucks (including Saturn) 2007 and Prior HUMMER H2, H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to change the repair information. Please discard Corporate Bulletin Number 63-20-02 (Section 8 - Body and Accessories). Because the energy absorbers are relatively low in cost to replace, it is now more cost efficient to replace the energy absorbers whenever they are damaged. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Bumper > Front Bumper > Front Bumper Shock Absorber > System Information > Technical Service Bulletins > Polypropylene Foam Energy Absorbers - Repair Front Bumper Shock Absorber: Technical Service Bulletins Polypropylene Foam Energy Absorbers - Repair File In Section: 10 - Body Bulletin No.: 63-20-02 Date: September, 1996 INFORMATION Subject: Repair of Polypropylene Foam Energy Absorbers Models: 1997 and Prior Passenger Cars Using Polypropylene Foam Energy Absorbers Some General Motors vehicles use a formed piece of Polypropylene foam as energy absorbers behind fascias. These energy absorbers (EA) are designed to offer a measure of safety in the event of a collision and have been engineered to withstand slight impacts (5 mph or less) with little or no damage. However, in some instances, the EA may crack or even break. The following information has been developed to offer an alternative to low impact EA replacements. The foam EA can be identified in most cases by the symbol "PP" molded into the surface. Following the procedure will allow the technician to repair an EA and return the vehicle to the original crashworthiness state. Polypropylene Foam EA Repair Procedure 1. If cracked or broken, make sure all the pieces of the EA are available for the repair. Important: If pieces of the EA are missing, the EA must be replaced. 2. Clean the areas to be bonded by brushing off any loose dirt or using soap and water, if necessary. Notice: DO NOT USE SOLVENTS TO CLEAN POLYPROPYLENE EA. The use of solvents may result in damage to the EA. 3. Using a 3M POLYGUN TC HOT MELT APPLICATOR GUN* and 3M JETMELT ADHESIVE # 3764*, apply adhesive to the parts by following the instructions for the applicator gun. Ensure complete wet out of the adhesive on the repair surfaces during reassembly of the EA. Important: The adhesive has a 40 second "work time" and requires a 2 minute "clamp time". Allow 20 minutes for the adhesive to fully cure. The "3M Polygun TC Hotmelt Applicator Gun" and "3M Jetmelt Adhesive # 3764" can be obtained by calling DIRECTECH at 1-800-877-9344 or 612-941-2616. * We believe this source and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Bumper > Rear Bumper > Rear Bumper Cover / Fascia > System Information > Technical Service Bulletins > Body - TPO Fascia Cleaning Prior to Painting Rear Bumper Cover / Fascia: Technical Service Bulletins Body - TPO Fascia Cleaning Prior to Painting INFORMATION Bulletin No.: 08-08-51-002 Date: March 12, 2008 Subject: New Primer For TPO Fascias and Affected Cleaning Process of Painting Operation Models: 2009 and Prior Passenger Cars and Trucks 2009 and Prior HUMMER H2, H3 The purpose of this bulletin is to inform the technician that General Motors has made a change in the primer it uses for TPO plastic for service parts. This new primer comes in several different colors from five different suppliers. This change affects the cleaning process of the painting operation. The new process is as follows. 1. Wash with soap and water. 2. Clean with a 50% mix of isopropyl alcohol and water (or a waterborne cleaner). Check with your paint supplier for product recommendations. 3. Scuff sand per your paint suppliers recommendations. Note: The use of a solvent-type cleaner will soften, or begin to dissolve the primer. Base coats do not have any affect on this primer. 4. Reclean with a 50% mix of isopropyl alcohol and water (or a waterborne cleaner). All fascias, with the exception of the Corvette, Camaro, and Cadillac XLR, are made of TPO. You may find other TPO parts with this primer. If the technician has a question as to the type of plastic they are painting, inspect the back of the part for the plastic symbol (TPO). Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Bumper > Rear Bumper > Rear Bumper Reinforcement > System Information > Technical Service Bulletins > Body - Polypropylene Energy Absorber Replacement Rear Bumper Reinforcement: Technical Service Bulletins Body - Polypropylene Energy Absorber Replacement Bulletin No.: 07-08-63-001 Date: April 17, 2007 INFORMATION Subject: Information on Repair of Polypropylene Energy Absorbers Models: 2007 and Prior GM Passenger Cars and Trucks (including Saturn) 2007 and Prior HUMMER H2, H3 2005-2007 Saab 9-7X Supercede: This bulletin is being revised to change the repair information. Please discard Corporate Bulletin Number 63-20-02 (Section 8 - Body and Accessories). Because the energy absorbers are relatively low in cost to replace, it is now more cost efficient to replace the energy absorbers whenever they are damaged. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Bumper > Rear Bumper > Rear Bumper Shock Absorber > System Information > Technical Service Bulletins > Polypropylene Foam Energy Absorbers - Repair Rear Bumper Shock Absorber: Technical Service Bulletins Polypropylene Foam Energy Absorbers - Repair File In Section: 10 - Body Bulletin No.: 63-20-02 Date: September, 1996 INFORMATION Subject: Repair of Polypropylene Foam Energy Absorbers Models: 1997 and Prior Passenger Cars Using Polypropylene Foam Energy Absorbers Some General Motors vehicles use a formed piece of Polypropylene foam as energy absorbers behind fascias. These energy absorbers (EA) are designed to offer a measure of safety in the event of a collision and have been engineered to withstand slight impacts (5 mph or less) with little or no damage. However, in some instances, the EA may crack or even break. The following information has been developed to offer an alternative to low impact EA replacements. The foam EA can be identified in most cases by the symbol "PP" molded into the surface. Following the procedure will allow the technician to repair an EA and return the vehicle to the original crashworthiness state. Polypropylene Foam EA Repair Procedure 1. If cracked or broken, make sure all the pieces of the EA are available for the repair. Important: If pieces of the EA are missing, the EA must be replaced. 2. Clean the areas to be bonded by brushing off any loose dirt or using soap and water, if necessary. Notice: DO NOT USE SOLVENTS TO CLEAN POLYPROPYLENE EA. The use of solvents may result in damage to the EA. 3. Using a 3M POLYGUN TC HOT MELT APPLICATOR GUN* and 3M JETMELT ADHESIVE # 3764*, apply adhesive to the parts by following the instructions for the applicator gun. Ensure complete wet out of the adhesive on the repair surfaces during reassembly of the EA. Important: The adhesive has a 40 second "work time" and requires a 2 minute "clamp time". Allow 20 minutes for the adhesive to fully cure. The "3M Polygun TC Hotmelt Applicator Gun" and "3M Jetmelt Adhesive # 3764" can be obtained by calling DIRECTECH at 1-800-877-9344 or 612-941-2616. * We believe this source and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Doors > Front Door > Front Door Window Glass > System Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information Front Door Window Glass: Technical Service Bulletins Body - Vehicle Glass Distortion Information INFORMATION Bulletin No.: 00-08-48-005D Date: September 10, 2010 Subject: Distortion in Outer Surface of Vehicle Glass Models: 2011 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 00-08-48-005C (Section 08 - Body and Accessories). Distortion in the outer surface of the windshield glass, door glass or backlite glass may appear after the vehicle has: - Accumulated some mileage. - Been frequently washed in automatic car washes, particularly "touchless" car washes. This distortion may look like a subtle orange peel pattern, or may look like a drip or sag etched into the surface of the glass. Some car wash solutions contain a buffered solution of hydrofluoric acid which is used to clean the glass. This should not cause a problem if used in the correct concentration. However, if not used correctly, hydrofluoric acid will attack the glass, and over time, will cause visual distortion in the outer surface of the glass which cannot be removed by scraping or polishing. If this condition is suspected, look at the area of the windshield under the wipers or below the belt seal on the side glass. The area of the glass below the wipers or belt seal will not be affected and what looks like a drip or sag may be apparent at the edge of the wiper or belt seal. You may also see a line on the glass where the wiper blade or the belt seal contacts the glass. Important The repair will require replacing the affected glass and is not a result of a defect in material or workmanship. Therefore, is not covered by New Vehicle Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Doors > Front Door > Front Door Window Glass > System Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information > Page 8582 Front Door Window Glass: Technical Service Bulletins Body - Side Window Chipping Information INFORMATION Bulletin No.: 06-08-64-001B Date: October 20, 2009 Subject: Information on Side Door Window Glass Chipping Caused by Hanging Vehicle Key Lock Box Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add vehicles and model years and to include all types of door window glass. Please discard Corporate Bulletin Number 06-08-64-001A (Section 08 - Body & Accessories). - In several warranty parts review cases, side door window glass was observed with a chip or chips on the top side of the window glass. Dealer contacts confirmed that they use a vehicle key lock box on the front side door window glass. - A random selection of side door glass returns will be conducted to confirm adherence. If a side door glass is discovered with a chip or chips in the location previously described, the side door glass will be returned to the dealership for debit. Example of Side Door Glass - DO NOT place a vehicle key lock box on a side door window glass. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Doors > Front Door > Front Door Window Glass > System Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information > Page 8583 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Hood > Hood Latch > Component Information > Locations > Hood Latch Assembly LH Radiator Support Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Hood > Hood Latch > Component Information > Locations > Hood Latch Assembly > Page 8589 Front Of Radiator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Power Trunk / Liftgate Lock Actuator > Component Information > Locations Rear Luggage Compartment With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Latch > Component Information > Technical Service Bulletins > Trap Resistant Trunk Kit - Function/Installation Trunk / Liftgate Latch: Technical Service Bulletins Trap Resistant Trunk Kit - Function/Installation File In Section: 08 - Body and Accessories Bulletin No.: 99-08-66-002A Date: January, 2000 Subject: Trap Resistant Rear Compartment (Trunk) Kit Models: 1990-2000 Passenger Cars with Rear Compartments Except: 1990-1991 Buick Reatta 2000 Buick LeSabre 1990-1993 Cadillac Allante, Fleetwood Brougham 1997-2000 Cadillac Seville 2000 Cadillac Deville 1990 Chevrolet Caprice 1990-1991 Chevrolet Cavalier 1990-1996 Chevrolet Beretta 1990-2000 Chevrolet Metro, Prizm 1998-2000 Chevrolet Corvette 2000 Chevrolet Impala 1990-1992 Oldsmobile Toronado/Trofeo 1990-1991 Pontiac Sunbird 1990-1993 Pontiac LeMans 2000 Pontiac Bonneville This bulletin is being revised to add additional models and new part numbers. Please discard Corporate Bulletin Number 99-O8-66-002 (Section 08 - Body and Accessories). The purpose of this bulletin is to inform dealership personnel about the Trap Resistant Rear Compartment (Trunk) Kit, including the system function, necessary vehicle modifications and part numbers required to install the kit. The Trap Resistant Rear Compartment kit is composed of three main system components; one of which (the Rear Seat Tether), may or may not be needed, depending on the vehicle being retrofit. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Latch > Component Information > Technical Service Bulletins > Trap Resistant Trunk Kit - Function/Installation > Page 8598 The first component of the kit is the illuminated Interior Release Handle (1). The Release Handle is mounted inside the rear compartment to the deck lid. This handle was designed so that a small child trapped in the rear compartment could use it to open the deck lid. The handle operates the deck lid latch mechanically, but is illuminated with two LED's when the deck lid is closed. The handle remains illuminated for a period of about one hour after the deck lid is closed. The LED's create a small parasitic load that will not drain the vehicle battery with normal usage. The second component of the kit is the Trap Resistant Latch (2). the Trap Resistant Latch is a modified deck lid latch designed to help prevent a child from unintentionally closing and latching the deck lid. The Trap Resistant Latch opens the rear compartment normally through all current means (key, RKE or passenger compartment release) but cannot be re-latched without the user performing a reset function. This reset function consists of pushing up on a small knob (3), while simultaneously pushing a slide mechanism to the right (4). Once the slide mechanism is fully pushed over, the small knob can be released. This function is a simple on-hand operation for an adult, but is difficult for a young child to perform. If the latch is not enabled, the deck lid will not latch and the rear compartment will not close. The third component is the Rear Seat Tether Kit. If the vehicle is equipped with a pass-through to the rear compartment and the folding rear seat can be unlatched from within the passenger compartment without the use of a key or other unlocking feature, then a Rear Seat Tether must be installed. This tether helps prevent a child from gaining access to the rear compartment of a vehicle from the passenger compartment by allowing a secondary lock of the seatback. The Rear Seat Tether employs one or two tethers (one per folding seatback), each permanently connected to a T-handle anchor mounted in the rear compartment. To lock the folding seatback, the user can partially fold the seatback and attach the tether to another T-handle anchor mounted to the seatback. When the tether is affixed to both T-handle anchors, the seat cannot be folded down. To fold down the seatback, the tether must be removed from the anchor attached to the seatback. Important: Installation of the Trap Resistant Latch on some vehicles may require sheet metal and/or trim modifications to the rear compartment striker area. These modifications should be communicated with the customer prior to installations. Also, installation of the Trap Resistant Latch requires a rear compartment lid "ajar" switch. Prior to ordering the Trap Resistant Rear Compartment Kit, inspect the old deck lid latch to see if it is equipped with an "ajar" switch. If the vehicle is not equipped with this switch, P/N 12506174 must be ordered. After completing the Trap Resistant Rear Compartment Kit installation, provide the customer with the supplemental Owner's Manual insert included in the kit and demonstrate the system function. This program is specially structured for a single purchase price to the owner. The owner is responsible to pay a maximum of $50.00 U.S.; $80.00 Canadian for parts and labor to install the complete Trap Resistant Rear Compartment Kit and Rear Seat Tether(s), if required. Parts Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Latch > Component Information > Technical Service Bulletins > Trap Resistant Trunk Kit - Function/Installation > Page 8599 Parts are currently available from GMSPO. Labor Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Solenoid > Component Information > Locations Trunk / Liftgate Solenoid: Locations Trunk Lid Trunk Lid With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Switch > Component Information > Locations > Component Locations Trunk / Liftgate Switch: Component Locations Trunk Lid With Pull-Down Back View Of LH Instrument Panel Rear Compartment Lid Enable Switch Mounted on I/P Compartment Rear Luggage Compartment With Pull-Down Rear Compartment Lid Pull-Down Striker Switch Attached to Rear Compartment Lid Pulldown Actuator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Switch > Component Information > Locations > Component Locations > Page 8610 Rear Compartment Lid Pull-Down Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Switch > Component Information > Locations > Component Locations > Page 8611 Trunk Lid With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Doors, Hood and Trunk > Trunk / Liftgate > Trunk / Liftgate Switch > Component Information > Locations > Page 8612 Rear Glass Interlock/Push Button Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Exterior Moulding / Trim > Body Emblem > Component Information > Technical Service Bulletins > 06-08-111-004B - BULLETIN CANCELLATION NOTIFICATION Body Emblem: Technical Service Bulletins 06-08-111-004B - BULLETIN CANCELLATION NOTIFICATION TECHNICAL Bulletin No.: 06-08-111-004B Date: September 25, 2009 Subject: Information on Discoloration, Blistering, Peeling or Erosion of Various Exterior Emblems Including Chevy Bowtie (Bulletin Cancelled) Models: 2009 and Prior GM Passenger Cars and Trucks (including Saturn) 2003-2009 HUMMER H2 2006-2009 HUMMER H3 2005-2009 Saab 9-7X Supercede: This bulletin is being cancelled. Please discard Corporate Bulletin Number 06-08-111-004A (Section 08 - Body & Accessories). This bulletin is being cancelled. The information is no longer applicable. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Frame > Cross-Member > Component Information > Locations Cross-Member: Locations Center Of Rear Crossmember Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Frame > Cross-Member > Component Information > Locations > Page 8622 Antilock Brake System Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Ash Tray > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Carpet > Component Information > Technical Service Bulletins > Interior - Proper Use of Floor Mats Carpet: Technical Service Bulletins Interior - Proper Use of Floor Mats INFORMATION Bulletin No.: 10-08-110-001 Date: March 30, 2010 Subject: Information on Proper Use of Floor Mats Models: 2011 and Prior GM Passenger Cars and Trucks (Including Saturn) 2003-2009 HUMMER H2 2006-2010 HUMMER H3, H3T 2005-2009 Saab 9-7X GM's carpeted and all-weather (rubber) floor mats are especially designed for use in specific GM vehicles. Using floor mats that were not designed for the specific vehicle or using them incorrectly may cause interference with the accelerator or brake pedal. Please review the following safety guidelines regarding proper driver's side floor mat usage with the customer. Warning If a floor mat is the wrong size or is not properly installed, it can interfere with the accelerator pedal and/or brake pedal. Interference with the pedals can cause unintended acceleration and/or increased stopping distance which can cause a crash and injury. Make sure the floor mat does not interfere with the accelerator or brake pedal. - Do not flip the driver's floor mat over (in an effort to keep the floor mat clean) - Do not place anything on top of the driver's floor mat (e.g. carpet remnant, towel) - Do not place another mat on top of the driver's floor mat (e.g. do not place all-weather rubber mats over carpeted floor mats) - Only use floor mats that are designed specifically for your vehicle - When using replacement mats, make certain the mats do not interfere with the accelerator or brake pedal before driving the vehicle If your vehicle is equipped with a floor mat retaining pin(s) or clip(s), make certain the mat is installed correctly and according to the instructions. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Carpet > Component Information > Technical Service Bulletins > Interior - Proper Use of Floor Mats > Page 8631 After installing floor mats, make certain they cannot move and do not interfere with the accelerator or brake pedals. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Carpet > Component Information > Technical Service Bulletins > Interior - Proper Use of Floor Mats > Page 8632 Carpet: Technical Service Bulletins Interior - Elimination Of Unwanted Odors INFORMATION Bulletin No.: 00-00-89-027E Date: September 29, 2008 Subject: Eliminating Unwanted Odors in Vehicles Models: 2009 and Prior GM Passenger Cars and Trucks (including Saturn) 2009 and Prior HUMMER H2, H3 Vehicles 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years and refine the instructions. Please discard Corporate Bulletin Number 00-00-89-027D (Section 00 - General Information). Vehicle Odor Elimination General Motors offers a product that may control or eliminate odors in the interior and luggage compartment areas of GM vehicles. GM Vehicle Care Odor Eliminator is a non-toxic, biodegradable odor remover. This odorless product has been shown to greatly reduce or remove objectionable smells of mold and mildew resulting from vehicle water leaks (as well as customer created odors, i.e. smoke). You may use GM Vehicle Care Odor Eliminator on fabrics, vinyl, leather, carpet and sound deadening materials. It may also be induced into HVAC modules and instrument panel ducts (for the control of non-bacterial related odors). Important: This product leaves no residual scent and should not be sold as or considered an air freshener. Product action may result in the permanent elimination of an odor and may be preferable to customers with allergies who are sensitive to perfumes. How to Use This Product GM Vehicle Care Odor Eliminator may be sprayed on in a ready-to-use formula or used in steam cleaners as an additive with carpet shampoo. This water-based, odorless product is safe for all vehicle interiors. Do not wet or soak any interior surface that plain water would cause to deteriorate, as this product will have the same effect. Also avoid letting this product come into contact with vinegar or any acidic substance. Acid-based products will hamper the effectiveness of, or render GM Vehicle Care Odor Eliminator inert. Note: Complete eight page treatment sheets are enclosed within each case of GM Vehicle Care Odor Eliminator. These treatment instructions range from simple vehicle odor elimination to full step by step procedures for odor removal from water leaks. If lost, contact 800-977-4145 to get a replacement set faxed or e-mailed to your dealership. Instructions and cautions are printed on the bottle, but additional help is available. If you encounter a difficult to eliminate or reoccurring odor, you may call 1-800-955-8591 (in Canada, 1-800-977-4145) to obtain additional information and usage suggestions. Important: This product may effectively remove odors when directly contacting the odor source. It should be used in conjunction with diagnostic procedures (in cases such as a water leak) to first eliminate the root cause of the odor, and then the residual odor to permanently correct the vehicle condition. Vehicle Waterleak Odor Elimination STEP ONE: Confirm that all water leaks have been repaired. Determine what areas of the vehicle were water soaked or wet. Components with visible mold/mildew staining should be replaced. Isolate the odor source inside the vehicle. Often an odor can be isolated to an area or component of the vehicle interior by careful evaluation. Odor evaluation may need to be performed by multiple persons. Another method of isolating an odor source is to remove and segregate interior trim and components. Plastic sheeting or drop cloths can be used to confine seats, headliners, etc. to assist in evaluation and diagnoses. If appropriate the vehicle and interior trim should be evaluated separately to determine if the odor stays with the vehicle or the interior components. Odors that stay with the vehicle may be isolated to insulating and sound deadening materials (i.e. water leak at the windshield or standing water in the front foot well area caused mold/mildew to form on the bulkhead or kick panel sound deadening pads. If the interior is removed the floor pan and primed/painted surfaces should be treated with bleach/soap solution, rinsed with clean water and dried. Interior surfaces should then be treated with GM Vehicle Care Odor Eliminator product before reinstalling carpet or reassembling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Carpet > Component Information > Technical Service Bulletins > Interior - Proper Use of Floor Mats > Page 8633 The GM Vehicle Care Odor Eliminator product is an effective odor elimination product when used properly. It must come into direct contact with the odor source. It should be used in conjunction with diagnostic procedures to first eliminate the root cause of the odor. Some procedures for use after odor root cause correction are: STEP TWO: ^ Use the trigger spray head. ^ Put a drop of dish soap the size of a quarter in the bottom of a bottle. ^ Add 8 oz. of GM Vehicle Care Odor Eliminator (1 cup) to the dish soap and top off the bottle with tap water. ^ This formula should be used on hard surfaces (dash, interior plastic molding, and floor pan) STEP THREE: The third step to neutralizing the vehicle is a light to medium treatment of all carpeting and upholstered seats with the GM Vehicle Care Odor Eliminator formula and a wide fan spray setting (at full strength) (i.e.: carpeting on the driver's side requires 4-5 triggers pulls for coverage). The headliner and trunk should be sprayed next. Lightly brushing the formula into the carpeting and upholstery is a recommended step for deep odor problems. The dash and all hard surfaces should be sprayed with dish soap/water mixture. Let stand for 1-2 minutes then wipe off the surface. STEP FOUR: (vehicle ventilation system treatment) The ventilation system is generally the last step in the treatment of the vehicle. a. Spray the GM Vehicle Care Odor Eliminator formula into all dash vents. (1-2 trigger pulls per vent). b. Start the vehicle and turn the vehicle fan on high cool (not A/C setting). c. Spray the formula (10 trigger pulls) into the outside fresh air intake vent (cowl at base of windshield) d. Enter the vehicle after 1 minute and wipe off the excess formula spurting out of the dash vents. e. Smell the air coming from the dash vents. If odors are still present, spray another 5 triggers into the cowl, wait another minute and smell the results. Once you have obtained a fresh, clean smell coming from the vents, turn the system to the A/C re-circulation setting. Roll up the windows, spray 3-5 pumps into the right lower IP area and let the vehicle run with the fan set on high for 5-7 minutes. Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. Additional Suggestions to Increase Customer Satisfaction Here are some additional ideas to benefit your dealership and to generate greater customer enthusiasm for this product. ^ Keep this product on-hand for both the Service Department and the Used Car lot. Add value to your used car trades; treat loaner and demo cars during service and at final sale to eliminate smoke, pet, and other common odors offensive to customers. Make deodorizing a vehicle part of your normal vehicle detailing service. ^ Consider including GM Vehicle Care Odor Eliminator as a give-away item with new vehicle purchases. Many dealers give away as "gifts" various cleaning supplies at time of delivery. GM Odor Eliminator is one of a few products GM offers that has as many uses in the home as in the vehicle. Customers may find this product can be used for a host of recreational activities associated with their new vehicle, such as deodorizing a boat they tow, or a camper. ^ GM Odor Eliminator and many of the GM Vehicle Care products offer you the chance to increase dealership traffic as these superior quality products cannot be purchased in stores. Many Dealerships have product displays at the parts counter. Consider additional displays in the Customer Service Lounge, the Showroom and at the Service Desk or Cashier Window. Many customers who purchase vehicles and receive regular maintenance at your dealership may never visit the parts counter, and subsequently are not exposed to the variety and value that these products offer. Parts Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Carpet > Component Information > Technical Service Bulletins > Interior - Proper Use of Floor Mats > Page 8634 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Dash Board / Instrument Panel <--> [Dashboard / Instrument Panel] > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming Air Bag(s) Arming and Disarming: Service and Repair Air Bag Disarming and Arming Disabling the SIR System The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Ensure front wheels are pointed straight ahead. 2. Turn ignition switch to LOCK position and remove SIR or AIR BAG fuse. 3. Remove Connector Position Assurance (CPA), then disconnect both yellow 2-way SIR electrical connectors at base of steering column. 4. Wait at least 2 minutes before proceeding with diagnosis or service. Enabling the SIR System 1. Connect both 2-way yellow connectors at base of steering column. 2. Install Connector Position Assurance (CPA). 3. Install SIR or AIR BAG fuse into fuse block. 4. Turn ignition to the RUN position and ensure that the "Inflatable Restraint lamp flashes seven to nine times and then turns off. If lamp does not operate as specified, refer to Testing And Inspection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Dash Board / Instrument Panel <--> [Dashboard / Instrument Panel] > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming > Page 8640 Air Bag(s) Arming and Disarming: Service and Repair General Service Precautions CAUTION; When performing service on or around SIR components or SIR wiring, follow the procedures to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Glove Compartment > Component Information > Technical Service Bulletins > I/P Compartment Door Latch/Lock Cylinder - Revised R&R; Glove Compartment: Technical Service Bulletins I/P Compartment Door Latch/Lock Cylinder Revised R&R; File In Section: 8 - Chassis/Body Electrical Bulletin No.: 63-83-05 Date: March, 1996 SERVICE MANUAL UPDATE Subject: Section 8C - Revised Remove/Install Procedure for I/P Compartment Door Latch and Lock Cylinder Assembly Models: 1994-96 Buick Roadmaster 1994-96 Cadillac Fleetwood 1994-96 Chevrolet Caprice, Impala This bulletin is being issued to revise the remove/install procedure for the I/P compartment door latch and lock cylinder assembly in Section 8C of the Service Manual. Instrument Panel compartment Door Latch and Lock Cylinder Assembly Figure 1 (Numbers indicated in parenthesis below refer to callout in Figure 1.) Remove or Disconnect 1. Open instrument panel (I/P) compartment door (6). 2. Bolts/screws (8) from door latch assembly. 3. Latch assembly from compartment door (6). 4. Place latch in lock position. 5. Lock cylinder assembly (5) from door latch assembly. a. Turn lock cylinder assembly (5) to lock position and remove key. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Interior Moulding / Trim > Glove Compartment > Component Information > Technical Service Bulletins > I/P Compartment Door Latch/Lock Cylinder - Revised R&R; > Page 8645 b. Using awl or paper clip, slightly depress lock tumbler by inserting paper clip through hole at base of cylinder housing. c. Insert key and remove awl or paper clip. d. Turn key and cylinder to full clockwise position (key head upside down). e. Remove lock cylinder assembly (5). Install or Connect 1. Lock cylinder assembly (5) to door latch assembly (5). a. Depress all lock tumblers on lock cylinder (5) with finger. b. Insert key into lock cylinder assembly (5). c. Insert key and lock cylinder assembly (5) into latch (key head upside down). d. Turn key to full counterclockwise position (key head right side up). e. Remove key. 2. Bolts/screws (8) attaching latch to I/P compartment door assembly (6). Tighten Tighten bolts/screws (8) to 1.9 N.m (17 lb. in.). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information Key: Technical Service Bulletins Locks - Key Code Security Rules and Information INFORMATION Bulletin No.: 10-00-89-010 Date: May 27, 2010 Subject: Key Code Security Rules and Information on GM KeyCode Look-Up Application (Canada Only) Models: 2011 and Prior GM Passenger Cars and Trucks 2010 and Prior HUMMER H2, H3 2009 and Prior Saturn and Saab 2002 and Prior Isuzu Attention: This bulletin has been created to address potential issues and questions regarding KeyCode security. This bulletin should be read by all parties involved in KeyCode activity, including dealer operator, partner security coordinator, sales, service and parts departments. A copy of this bulletin should be printed and maintained in the parts department for use as a reference. Important U.S. dealers should refer to Corporate Bulletin Number 10-00-89-009. Where Are Key Codes Located? General Motors provides access to KeyCodes through three sources when a vehicle is delivered to a dealer. Vehicle KeyCodes are located on the original vehicle invoice to the dealership. There is a small white bar coded tag sent with most new vehicles that also has the key code printed on it. Dealerships should make a practice of comparing the tag's keycode numbers to the keycode listed on the invoice. Any discrepancy should be reported immediately to the GM of Canada Key Code Inquiry Desk. Remember to remove the key tag prior to showing vehicles to potential customers. The third source for Key codes is through the GM KeyCode Look-Up feature within the OEConnection D2DLink application. KeyCode Look-Up currently goes back 17 previous model years from the current model year. When a vehicle is received by the dealership, care should be taken to safeguard the original vehicle invoice and KeyCode tag provided with the vehicle. Potential customers should not have access to the invoice or this KeyCode tag prior to the sale being completed. After a sale has been completed, the KeyCode information belongs to the customer and General Motors. Tip Only the original invoice contains key code information, a re-printed invoice does not. GM KeyCode Look-Up Application for GM of Canada Dealers All dealers should review the General Motors of Canada KeyCode Look-Up Policies and Procedures (Service Policy & Procedures Manual Section 3.1.6 "Replacement of VIN plates & keys"). Please note that the KeyCode Access site is restricted. Only authorized users should be using this application. Please see your Parts Manager for site authorized users. KeyCode Look-Up currently goes back 17 years from current model year. Important notes about security: - Users may not access the system from multiple computers simultaneously. - Users may only request one KeyCode at a time. - KeyCode information will only be available on the screen for 2 minutes. - Each user is personally responsible for maintaining and protecting their password. - Never share your password with others. - User Id's are suspended after 6 consecutive failed attempts. - User Id's are disabled if not used for 90 days. - Processes must be in place for regular dealership reviews. - The Parts Manager (or assigned management) must have processes in place for employee termination or life change events. Upon termination individuals access must be turned off immediately and access should be re-evaluated upon any position changes within the dealership. - If you think your password or ID security has been breached, contact Dealer Systems Support at 1-800-265-0573. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information > Page 8651 Each user will be required to accept the following agreement each time the KeyCode application is used. Key Code User Agreement - Key codes are proprietary information belonging to General Motors Corporation and to the vehicle owner. - Unauthorized access to, or use of, key code information is unlawful and may subject the user to criminal and civil penalties. - This information should be treated as strictly confidential and should not be disclosed to anyone unless authorized. I will ensure that the following information is obtained prior to releasing any Key Code information: 1. Government issued picture ID (Drivers License) 2. Registration or other proof of ownership. Registration should have normal markings from the Province that issued the registration and possibly the receipt for payment recorded as well. Important - GM takes this agreement seriously. Each user must be certain of vehicle ownership before giving out key codes. - When the ownership of the vehicle is in doubt, dealership personnel should not provide the information. Key code requests should never be received via a fax or the internet and key codes should never be provided to anyone in this manner. A face to face contact with the owner of the vehicle is the expected manner that dealers will use to release a key code or as otherwise stipulated in this bulletin or other materials. - Key codes should NEVER be sent via a fax or the internet. - Each Dealership should create a permanent file to document all KeyCode Look Up transactions. Requests should be filed by VIN and in each folder retain copies of the following: - Government issued picture ID (Drivers License) - Registration or other proof of ownership. - Copy of the paid customer receipt which has the name of the employee who cut and sold the key to the customer. - Do not put yourself or your Dealership in the position of needing to "explain" a KeyCode Look Up to either GM or law enforcement officials. - Dealership Management has the ability to review all KeyCode Look-Up transactions. - Dealership KeyCode documentation must be retained for two years. Frequently Asked Questions (FAQs) for GM of Canada Dealers How do I request a KeyCode for customer owned vehicle that is not registered? Scrapped, salvaged or stored vehicles that do not have a current registration should still have the ownership verified by requesting the vehicle title, current insurance policy and / or current lien holder information from the customers financing source. If you cannot determine if the customer is the owner of the vehicle, do not provide the key code information. In these cases, a short description of the vehicle (scrapped, salvaged, etc.) and the dealership location should be kept on file. Any clarifying explanation should be entered into the comments field. How do I document a KeyCode request for a vehicle that is being repossessed? The repossessor must document ownership of the vehicle by providing a court ordered repossession order and lien-holder documents prior to providing key code information. Copies of the repossessors Drivers License and a business card should be retained by the dealership for documentation. What do I do if the registration information is locked in the vehicle? Every effort should be made to obtain complete information for each request. Each Dealership will have to decide on a case by case basis if enough information is available to verify the customer's ownership of the vehicle. Other forms of documentation include vehicle title, insurance policy, and or current lien information from the customers financing source. Dealership Management must be involved in any request without complete information. If you cannot determine if the customer is the owner of the vehicle, do not provide the key code information. Can I get a print out of the information on the screen? It is important to note that the Key Code Look Up Search Results contain sensitive and/or proprietary information. For this reason GM recommends against printing it. If the Search Results must be printed, store and/or dispose of the printed copy properly to minimize the risk of improper or illegal use. Who in the dealership has access to the KeyCode application? Dealership Parts Manager (or assigned management) will determine, and control, who is authorized to access the KeyCode Look Up application. However, we anticipate that dealership parts and service management will be the primary users of the application. The KeyCode Look Up application automatically tracks each user activity session. Information tracked by the system includes: User name, User ID, all other entered data and the date/time of access. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information > Page 8652 What if I input the VIN incorrectly? If an incorrect VIN is entered into the system (meaning that the system does not recognize the VIN or that the VIN has been entered incorrectly) the system will return an error message. If I am an authorized user for the KeyCode application, can I access the application from home? Yes. What if I suspect key code misuse? Your dealership should communicate the proper procedures for requesting key codes. Any suspicious activity either within the dealership or externally should be reported to Dealer Systems Support at 1-800-265-0573 or GM of Canada Key Code Inquiry Desk at 1-905-644-4892. Whose key codes can I access through the system? At this time the following Canadian vehicle codes are available through the system: Chevrolet, Cadillac, Buick, Pontiac, GMC, HUMMER (H2 and H3 only), Oldsmobile, Saturn, Saab and Isuzu (up to 2002 model year) for a maximum of 17 model years. What should I do if I enter a valid VIN and the system does not produce any key code information? Occasionally, the KeyCode Look Up application may not produce a key code for a valid VIN. This may be the result of new vehicle information not yet available. In addition, older vehicle information may have been sent to an archive status. If you do not receive a key code returned for valid VIN, you should contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. How do I access KeyCodes if the KeyCode Look-up system is down? If the KeyCode Look-up system is temporarily unavailable, you can contact the original selling dealer who may have it on file or contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. If the customer is dealing with an emergency lock-out situation, you need to have the customer contact Roadside assistance, OnStar if subscribed, or 911. What should I do if the KeyCode from the look-up system does not work on the vehicle? On occasion a dealer may encounter a KeyCode that will not work on the vehicle in question. In cases where the KeyCode won't work you will need to verify with the manufacturer of the cutting equipment that the key has been cut correctly. If the key has been cut correctly you may be able to verify the proper KeyCode was given through the original selling dealer. When unable to verify the KeyCode through the original selling dealer contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. If the key has been cut correctly and the code given does not work, the lock cylinder may have been changed. In these situations following the proper SI document for recoding a key or replacing the lock cylinder may be necessary. How long do I have to keep KeyCode Records? Dealership KeyCode documentation must be retained for two years. Can I get a KeyCode changed in the Look-Up system? Yes, KeyCodes can be changed in the Look-Up system if a lock cylinder has been changed. Contact GM of Canada Key Code Inquiry Desk at 1-905-644-4892. What information do I need before I can provide a driver of a company fleet vehicle Keys or KeyCode information? The dealership should have a copy of the individual's driver's license, proof of employment and registration. If there is any question as to the customer's employment by the fleet company, the dealer should attempt to contact the fleet company for verification. If there is not enough information to determine ownership and employment, this information should not be provided. How do I document a request from an Independent Repair facility for a KeyCode or Key? The independent must provide a copy of their driver's license, proof of employment and signed copy of the repair order for that repair facility. The repair order must include customer's name, address, VIN, city, province and license plate number. Copies of this information must be included in your dealer KeyCode file. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Key > Component Information > Technical Service Bulletins > Locks - Key Code Security Rules and Information > Page 8653 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Programming Connector > Component Information > Locations Keyless Entry Programming Connector: Locations LH Luggage Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Receiver > Component Information > Locations Rear Shelf, Top View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Receiver > Component Information > Locations > Page 8661 Keyless Entry Receiver: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Receiver > Component Information > Locations > Page 8662 C406: Body Harness To Tailgate Harness, Headlamp Automatic Control Module (C1), Remote Control Door Lock Receiver Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Transmitter > Component Information > Technical Service Bulletins > Tools - Keyless Entry Transmitter Tester Keyless Entry Transmitter: Technical Service Bulletins Tools - Keyless Entry Transmitter Tester File In Section: 9 - Accessories Bulletin No.: 83-90-12 Date: August, 1998 INFORMATION Subject: Essential Tool J 43241 Remote Keyless Entry and Passive Keyless Entry Transmitter Tester Models: 1990-99 Passenger Cars and Trucks with Remote Keyless Entry or Passive Keyless Entry Systems A new essential tool, J 43241 Remote Keyless Entry Transmitter Tester, has been sent to all GM Dealers. This tester can be used on all RKE and PKE systems, on past as well as current models. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Transmitter > Component Information > Technical Service Bulletins > Tools - Keyless Entry Transmitter Tester > Page 8667 Important: Before using the tester and the diagnostic chart, the following two steps must be performed. 1. Verify that the keyless entry transmitter is the correct model for the vehicle remote system. An incorrect model transmitter may pass this test, but may not activate the vehicle remote system. The correct transmitter can usually be identified by part number. 2. Ensure that the transmitter is synchronized with the vehicle (if applicable). Refer to Transmitter Synchronization in the appropriate Service Manual. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Remote Keyless Entry <--> [Keyless Entry] > Keyless Entry Transmitter > Component Information > Technical Service Bulletins > Page 8668 Keyless Entry Transmitter: Service and Repair 1. Reposition rear compartment trim to access the programming connector located at the left of the rear compartment, for sedan. 2. Remove right back body pillar finish panel to access programming connector, for wagon. 3. Ground the programming connector by connecting the terminals together. ^ The system will verify this has occurred by performing a lock all, unlock drivers door/unlock all, and trunk/endgate cycle. 4. Press any key on either transmitter. ^ This step programs that particular transmitter to the receiver. ^ The system will verify by performing the same lock/unlock, lock/unlock cycle. 5. The Automatic Door Locking/Unlocking function is automatically enabled for this transmitter. To leave it enabled, skip to step 6. To disable the Automatic Door Locking/Unlocking function for this transmitter, perform the following sequence 3 times. A. Press the door lock button within 1 second of step C the 2nd and 3rd time through this sequence. B. Press the door unlock button within 1 second of step A. C Press the trunk button within 1 second of step B. ^ The receiver will cycle through the lock, unlock, trunk sequence 3 times as verification. 6. To program a second transmitter to the receiver, repeat step 4 with the second transmitter. Otherwise, go to 7. 7. Disconnect the programming connector. ^ System will not operate if ground connection is not removed. 8. Verify operation of each transmitter. 9. Reposition rear compartment trim, for sedan. 10. Install right back body pillar finish panel, for wagon. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Actuator > Component Information > Locations > Left Front LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Actuator > Component Information > Locations > Left Front > Page 8674 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Actuator > Component Information > Locations > Left Front > Page 8675 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Actuator > Component Information > Locations > Left Front > Page 8676 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Relay > Component Information > Locations Power Door Lock Relay: Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Relay > Component Information > Locations > Page 8680 Base Of LH A Pillar With Power Door Locks Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Relay > Component Information > Locations > Page 8681 Power Door Lock Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Switch > Component Information > Locations > Component Locations Power Door Lock Switch: Component Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Switch > Component Information > Locations > Component Locations > Page 8686 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Switch > Component Information > Locations > Component Locations > Page 8687 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Locks > Power Locks > Power Door Lock Switch > Component Information > Locations > Page 8688 Power Door Lock Switch RH And LH Front Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Mirrors > Heated Element, Mirror > Component Information > Technical Service Bulletins > Mirrors - Heated Mirrors, Defrosting Time Heated Element: Technical Service Bulletins Mirrors - Heated Mirrors, Defrosting Time INFORMATION Bulletin No.: 08-08-64-011A Date: February 25, 2010 Subject: Information on Heated Electrochromatic Outside Rearview Mirror Performance Models: 2010 and Prior GM Passenger Cars and Light Duty Trucks (including Saturn) 2009 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to update the model years. Please discard Corporate Bulletin Number 08-08-64-011 (Section 08 - Body and Accessories). Defrosting Time/Performance Concern The electrochromatic (auto-dimming) outside rearview mirror used on the driver's side of many GM vehicles is slower to defrost than the passenger side outside rearview mirror. This is a normal condition. The glass on the driver's side electrochromatic mirror is twice as thick as the traditional glass on the passenger side mirror. The heating elements for the mirrors on both sides draw the same wattage, therefore the driver's side mirror will take approximately twice as long to defrost as the passenger mirror (approximately four minutes versus two minutes). Should a customer indicate that the driver's side heated mirror is not functioning correctly, verify it's function based upon this information prior to replacing the mirror. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Mirrors > Memory Positioning Systems > Memory Positioning Module > Component Information > Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Mirrors > Memory Positioning Systems > Seat Memory Switch > Component Information > Locations Seat Memory Switch: Locations LH Front door on armrest Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Mirrors > Power Mirror Switch > Component Information > Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > Customer Interest: > 05-08-51-008C > Jun > 09 > Body - Bumps or Rust Colored Spots in Paint Paint: Customer Interest Body - Bumps or Rust Colored Spots in Paint TECHNICAL Bulletin No.: 05-08-51-008C Date: June 22, 2009 Subject: Bumps or Rust Colored Spots in Paint Due to Rail or Iron Dust (Remove Rail Dust) Models: 1994-2010 GM Passenger Cars and Trucks (Including Saturn) 2003-2010 HUMMER H2 2006-2010 HUMMER H3 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 05-08-51-008B (Section 08 - Body and Accessories). Condition Visible rust colored spots or bumps on a vehicle's paint surface from rail or iron dust. Cause Rail dust comes from tiny iron particles produced from the friction between train wheels and the tracks and gets deposited on the vehicle surfaces. Iron dust can get deposited on the surface if the vehicle is stored near any operation producing iron dust such as an iron ore yard. Either material can lay on top of, or become embedded in, the paint surface. Correction Because the severity of the condition varies, proper diagnosis of the damage is critical to the success of repairs. Diagnosis should be performed on horizontal surfaces (hood, roof, deck lid, pick up box, etc.) after the vehicle has been properly cleaned. There are two types of repair materials recommended to repair rail dust or iron dust: 1. GEL TYPE OXALIC ACID: - Has the characteristics of the liquid type oxalic acid but stays where you put it because of its gel consistency. 2. CLAY TYPE NON-ACID BASED: - Requires surface lubricant during use. - Has different grades available. Caution Rail dust remover (Oxalic Acid) is an acidic substance containing chemicals that will break down the iron particles embedded in the finish. When working with rail dust remover, use the necessary safety equipment, including gloves and goggles. Follow the chemical manufacturer's directions closely because it may require special handling and disposal. If, upon inspection, some particles are still present, the various chemical manufacturer's processes can be repeated. After the removal process, small pits may remain in the clearcoat and can be corrected, in most cases, with a finesse/polish operation. Procedure 1. Move the vehicle to a cool shaded area and make sure that the vehicle surfaces are cool during the removal process. DO NOT PERFORM THE REMOVAL PROCESS IN DIRECT SUNLIGHT OR ON A VEHICLE WITH HOT OR WARM BODY PANELS. 2. Wash the vehicle with soap and water. Dry it immediately and clean the affected areas with a wax and grease remover. 3. Perform the removal process according to the chemical manufacturer's directions. Once the damage has been repaired, the final step involves a polishing process. Rail Dust Remover Manufacturers Use the chemical manufacturers listed below, or equivalent: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > Customer Interest: > 05-08-51-008C > Jun > 09 > Body - Bumps or Rust Colored Spots in Paint > Page 8713 Auto Magic(R) or Clay Magic(R) products available from: Auto Wax Company, Inc. 1275 Round Table Dr. Dallas, TX 75247 (800) 826-0828 (Toll-Free) or (214) 631-4000 (Local) Fax (214) 634-1342 www.automagic.com [email protected] E038 Fallout Gel or E038E Liquid Fallout Remover II available from: Valvoline Car Brite Company 1910 South State Avenue Indianapolis, In 46203 (800) 347-2439 (Toll Free) or (317) 788-9925 (Local) Fax (317) 788-9930 www.carbrite.com [email protected] *We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources. If rail dust remover is not available in your area, call one of the numbers listed above for a distributor near your location. Warranty Information (excluding Saab U.S. Models) Important Refer to the Policy & Procedures Manual, section 1.2.1.7 for detailed information regarding warranty coverage for this condition. Important In certain cases where the vehicle finish is severely damaged and the actual repair time exceeds the published time, the additional time should be submitted in the "Other Labor Hours" field. Warranty Information (Saab U.S. Models) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > Customer Interest: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler Paint: Customer Interest Exhaust System - Paint Peeling from Painted Muffler File In Section: 10 - Body Bulletin No.: 33-17-01A Date: December, 1997 Subject: Paint Peeling from Muffler (New Repair Paint Available) Models: 1993-98 Passenger Cars with Painted Mufflers This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 33-17-01 (Section 10 - Body). Condition Some owners may experience paint peeling from the muffler. Correction Clean and repaint the affected area using the following procedure and product. Important: DO NOT REPLACE COMPONENTS TO REPAIR THIS CONDITION. The exhaust system must be cold to begin this procedure. Material Required: * Wabash Products # KB-318-HHHS, available in pints or quarts as ready to spray material (no mixing required). Call Wabash Products, 1-800-326-7269 or 812-232-6097 for pricing and shipping information. Procedure On a cold exhaust system: 1. Raise vehicle on hoist. 2. While supporting exhaust with a transmission jack, remove the rear exhaust system hangers and lower the exhaust. 3. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 4. Wire brush the affected area to remove flaking paint and blow off with air. 5. Sand the affected area with # 80 to 150 grit sandpaper to remove rust, dirt or other contaminants. 6. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 7. Tape off the rear lower body panels and exhaust pipes forward of mufflers to protect from overspray. 8. Apply paint to affected area in several (6 to 8) thin coats (to prevent sags and runs) obtaining approximately 1 mil paint coverage. 9. Raise exhaust system with jack, reinstall exhaust hangers, lower vehicle and remove from hoist. ^ Allow 30 minutes drying time. 10. In a well ventilated area, start engine and allow to idle for up to 30 minutes until paint is cured and dry. Important: Some "smoking" will occur while curing the paint with the engine running. The paint can be heated and cured while driving, but be careful not to get the exhaust system wet during the first 30 minutes. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > Customer Interest: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler > Page 8718 Labor Material Operation Labor Time Allowance A6150 0.6 hr - Single Exhaust GC Add 0.2 hr - Dual Exhaust GC Important: While the above procedure and materials are correct for vehicles from 1993 to 1998, the Labor Operation and Time Allowance only pertains to vehicles in the Warranty period. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 05-08-51-008C > Jun > 09 > Body - Bumps or Rust Colored Spots in Paint Paint: All Technical Service Bulletins Body - Bumps or Rust Colored Spots in Paint TECHNICAL Bulletin No.: 05-08-51-008C Date: June 22, 2009 Subject: Bumps or Rust Colored Spots in Paint Due to Rail or Iron Dust (Remove Rail Dust) Models: 1994-2010 GM Passenger Cars and Trucks (Including Saturn) 2003-2010 HUMMER H2 2006-2010 HUMMER H3 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 05-08-51-008B (Section 08 - Body and Accessories). Condition Visible rust colored spots or bumps on a vehicle's paint surface from rail or iron dust. Cause Rail dust comes from tiny iron particles produced from the friction between train wheels and the tracks and gets deposited on the vehicle surfaces. Iron dust can get deposited on the surface if the vehicle is stored near any operation producing iron dust such as an iron ore yard. Either material can lay on top of, or become embedded in, the paint surface. Correction Because the severity of the condition varies, proper diagnosis of the damage is critical to the success of repairs. Diagnosis should be performed on horizontal surfaces (hood, roof, deck lid, pick up box, etc.) after the vehicle has been properly cleaned. There are two types of repair materials recommended to repair rail dust or iron dust: 1. GEL TYPE OXALIC ACID: - Has the characteristics of the liquid type oxalic acid but stays where you put it because of its gel consistency. 2. CLAY TYPE NON-ACID BASED: - Requires surface lubricant during use. - Has different grades available. Caution Rail dust remover (Oxalic Acid) is an acidic substance containing chemicals that will break down the iron particles embedded in the finish. When working with rail dust remover, use the necessary safety equipment, including gloves and goggles. Follow the chemical manufacturer's directions closely because it may require special handling and disposal. If, upon inspection, some particles are still present, the various chemical manufacturer's processes can be repeated. After the removal process, small pits may remain in the clearcoat and can be corrected, in most cases, with a finesse/polish operation. Procedure 1. Move the vehicle to a cool shaded area and make sure that the vehicle surfaces are cool during the removal process. DO NOT PERFORM THE REMOVAL PROCESS IN DIRECT SUNLIGHT OR ON A VEHICLE WITH HOT OR WARM BODY PANELS. 2. Wash the vehicle with soap and water. Dry it immediately and clean the affected areas with a wax and grease remover. 3. Perform the removal process according to the chemical manufacturer's directions. Once the damage has been repaired, the final step involves a polishing process. Rail Dust Remover Manufacturers Use the chemical manufacturers listed below, or equivalent: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 05-08-51-008C > Jun > 09 > Body - Bumps or Rust Colored Spots in Paint > Page 8724 Auto Magic(R) or Clay Magic(R) products available from: Auto Wax Company, Inc. 1275 Round Table Dr. Dallas, TX 75247 (800) 826-0828 (Toll-Free) or (214) 631-4000 (Local) Fax (214) 634-1342 www.automagic.com [email protected] E038 Fallout Gel or E038E Liquid Fallout Remover II available from: Valvoline Car Brite Company 1910 South State Avenue Indianapolis, In 46203 (800) 347-2439 (Toll Free) or (317) 788-9925 (Local) Fax (317) 788-9930 www.carbrite.com [email protected] *We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources. If rail dust remover is not available in your area, call one of the numbers listed above for a distributor near your location. Warranty Information (excluding Saab U.S. Models) Important Refer to the Policy & Procedures Manual, section 1.2.1.7 for detailed information regarding warranty coverage for this condition. Important In certain cases where the vehicle finish is severely damaged and the actual repair time exceeds the published time, the additional time should be submitted in the "Other Labor Hours" field. Warranty Information (Saab U.S. Models) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 08-08-51-002 > Mar > 08 > Body - TPO Fascia Cleaning Prior to Painting Paint: All Technical Service Bulletins Body - TPO Fascia Cleaning Prior to Painting INFORMATION Bulletin No.: 08-08-51-002 Date: March 12, 2008 Subject: New Primer For TPO Fascias and Affected Cleaning Process of Painting Operation Models: 2009 and Prior Passenger Cars and Trucks 2009 and Prior HUMMER H2, H3 The purpose of this bulletin is to inform the technician that General Motors has made a change in the primer it uses for TPO plastic for service parts. This new primer comes in several different colors from five different suppliers. This change affects the cleaning process of the painting operation. The new process is as follows. 1. Wash with soap and water. 2. Clean with a 50% mix of isopropyl alcohol and water (or a waterborne cleaner). Check with your paint supplier for product recommendations. 3. Scuff sand per your paint suppliers recommendations. Note: The use of a solvent-type cleaner will soften, or begin to dissolve the primer. Base coats do not have any affect on this primer. 4. Reclean with a 50% mix of isopropyl alcohol and water (or a waterborne cleaner). All fascias, with the exception of the Corvette, Camaro, and Cadillac XLR, are made of TPO. You may find other TPO parts with this primer. If the technician has a question as to the type of plastic they are painting, inspect the back of the part for the plastic symbol (TPO). Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler Paint: All Technical Service Bulletins Exhaust System - Paint Peeling from Painted Muffler File In Section: 10 - Body Bulletin No.: 33-17-01A Date: December, 1997 Subject: Paint Peeling from Muffler (New Repair Paint Available) Models: 1993-98 Passenger Cars with Painted Mufflers This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 33-17-01 (Section 10 - Body). Condition Some owners may experience paint peeling from the muffler. Correction Clean and repaint the affected area using the following procedure and product. Important: DO NOT REPLACE COMPONENTS TO REPAIR THIS CONDITION. The exhaust system must be cold to begin this procedure. Material Required: * Wabash Products # KB-318-HHHS, available in pints or quarts as ready to spray material (no mixing required). Call Wabash Products, 1-800-326-7269 or 812-232-6097 for pricing and shipping information. Procedure On a cold exhaust system: 1. Raise vehicle on hoist. 2. While supporting exhaust with a transmission jack, remove the rear exhaust system hangers and lower the exhaust. 3. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 4. Wire brush the affected area to remove flaking paint and blow off with air. 5. Sand the affected area with # 80 to 150 grit sandpaper to remove rust, dirt or other contaminants. 6. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 7. Tape off the rear lower body panels and exhaust pipes forward of mufflers to protect from overspray. 8. Apply paint to affected area in several (6 to 8) thin coats (to prevent sags and runs) obtaining approximately 1 mil paint coverage. 9. Raise exhaust system with jack, reinstall exhaust hangers, lower vehicle and remove from hoist. ^ Allow 30 minutes drying time. 10. In a well ventilated area, start engine and allow to idle for up to 30 minutes until paint is cured and dry. Important: Some "smoking" will occur while curing the paint with the engine running. The paint can be heated and cured while driving, but be careful not to get the exhaust system wet during the first 30 minutes. Warranty Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 33-17-01A > Dec > 97 > Exhaust System - Paint Peeling from Painted Muffler > Page 8733 Labor Material Operation Labor Time Allowance A6150 0.6 hr - Single Exhaust GC Add 0.2 hr - Dual Exhaust GC Important: While the above procedure and materials are correct for vehicles from 1993 to 1998, the Labor Operation and Time Allowance only pertains to vehicles in the Warranty period. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 72-05-11 > Dec > 97 > Warranty - Rail Dust Removal & Chemical Spotting Labor Paint: All Technical Service Bulletins Warranty - Rail Dust Removal & Chemical Spotting Labor File In Section: Warranty Administration Bulletin No.: 72-05-11 Date: December, 1997 WARRANTY ADMINISTRATION Subject: Clarification of Rail Dust Removal (A5575-A5580) and Chemical Spotting (A5541-A5544) Labor Operations Models: All Past and Future Passenger Cars and Light Duty Trucks The purpose of this Warranty Administration Bulletin is to clarify the usage, limits and guidelines for the proper use of the above subject labor operations. The above subject labor operations were introduced to correct paint imperfections caused by fallout that occurred either during shipment to the dealer or within the first 12 months or 12,000 miles (20,000 kms) of vehicle ownership. GM vehicle owners are informed that although no defect in the factory applied paint causes this, GM will repair, at no charge to the owner, the surfaces of new vehicles damaged by fallout condition within 12 months or 12,000 miles (20,000 kms) whichever occurs first. Effective with repair orders dated on or after December 1, 1997, labor operations A5575-A5580 Rail Dust Removal and A5541 through A5544 Chemical Spotting will be limited to within the first 12 months or 12,000 miles of the Base Vehicle Warranty (20,000 kms) whichever occurs first. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 63-17-07B > Jun > 97 > Paint - Basecoat/Clearcoat Paint Systems Specifications Paint: All Technical Service Bulletins Paint - Basecoat/Clearcoat Paint Systems Specifications File In Section: 10 - Body Bulletin No.: 63-17-07B Date: June, 1997 INFORMATION Subject: New Aftermarket Paint Specification (GM4901M) for Basecoat/Clearcoat Paint Systems (Rigid Exterior Surfaces) Models: 1993-97 Passenger Cars and Trucks This bulletin is being revised to provide additional information on approved paint systems (Attachment 1 added). Please discard Corporate Bulletin Number 63-17-07A (Section 10 - Body). A vehicle's appearance is important to any customer's perception of that vehicle's quality and value. Furthermore, when an exterior finish repair is made, the customer expects that repair to match the showroom finish. Based upon rigorous and exhaustive testing, General Motors has established an aftermarket refinish paint specification, known as GM4901M, which is listed in the GM Engineering Specifications Manual. Use this specification when selecting a paint system for General Motors vehicle warranty paint repairs. All major paint suppliers are involved and support this program. The booklet enclosed with Corporate Bulletin # 63-17-07, "GM Approved Refinish Materials", P/N GM4901 M-D, identifies the paint systems you may use. All approved products (including VOC-compliant) are listed in the "system" approach recommended by the individual manufacturer. This booklet will be updated periodically to ensure you are provided with the latest information on paint systems. GM and Paint Supplier training services encompass this new specification and can address any questions. All materials listed in the booklet fall under the current materials allowance. However, this may change as costs increase. With this program, it is our goal to ensure quality repairs. After all, skilled technicians using the right materials offer the only path to true customer enthusiasm. By adhering to the GM4901M Specification for Aftermarket Paint Repair Materials, you will ensure our customers only receive the best while maximizing your quality throughout on exterior finish repairs. When a meeting or training session is held in your area, be sure your team is represented. We look forward to your support for this program. Additional Information In the development of this paint specification, major paint suppliers were invited to submit materials for approval. The requirements of the program are included in the approved materials booklet referenced above, dated December, 1996. Important: As of 7-1-97, the BASF products listed on Attachment 1 are now approved for use. The approved suppliers are: ^ Akzo Nobel (Sikkens) ^ American Standox ^ BASF ^ DuPont ^ ICI Autocolor ^ Martin Senour ^ PPG ^ Sherwin Williams Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 63-17-07B > Jun > 97 > Paint - Basecoat/Clearcoat Paint Systems Specifications > Page 8742 ^ Spies Hecker Your Zone wholesale personnel, Training Centers, STG Field Service Engineers, and the approved suppliers have additional training materials that may answer your further questions. Use of these GM approved materials ensures the highest quality for maintaining customer satisfaction. The dealer or retailer must ensure that all refinish materials, including sublets, meet GM Specification GM4901-M. Use of materials (and associated application methods) that do not meet this GM standard may result in a review of claim(s) leading to chargeback(s), as specified in the Policies and Procedures manual, Article 1.4.17. The standards will be updated periodically and other suppliers may be added when new standards are released by the fall of 1997. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 63-17-07B > Jun > 97 > Paint - Basecoat/Clearcoat Paint Systems Specifications > Page 8743 ATTACHMENT 1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 43-01-03A > Dec > 95 > Paint - Information and SPID Label Paint: All Technical Service Bulletins Paint - Information and SPID Label File In Section: 0 - General Information Bulletin No.: 43-01-03A Date: December, 1995 INFORMATION Subject: SPID Label and Paint information Models: 1995-96 Passenger Cars and Trucks This bulletin is being revised to add the 1996 model year. Please discard Corporate Bulletin Number 43-01-03 (Section 0 - General Information). The information concerns the service parts identification label (SPID) location on all 1995-96 vehicles and the paint information location on those labels. Important: There may be a label location change for the F-car (interim 1996-1/2 model year). When the interim production change occurs, the label may be located on the left door jamb. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 43-01-03A > Dec > 95 > Paint - Information and SPID Label > Page 8748 1995-96 GENERAL MOTORS Vehicle Paint Identification SERVICE PARTS IDENTIFICATION LABEL LOCATIONS Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 43-01-03A > Dec > 95 > Paint - Information and SPID Label > Page 8749 PAINT CODE EXPLANATIONS SERVICE PARTS IDENTIFICATION LABEL The Service Parts Identification Label (below) is a paper material with a protective plastic coating. It is being used to replace the metal Fisher Body plate. The label should provide the following: ^ Vehicle Identification Number (VIN) ^ "WA" Number ^ Two-Digit Paint Code ^ Paint Technology ^ Vinyl Top Color (where applicable) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 43-01-03A > Dec > 95 > Paint - Information and SPID Label > Page 8750 ^ Interior Color Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 531704 > Sep > 95 > Paint - Polishing And Swirl Mark Removal Paint: All Technical Service Bulletins Paint - Polishing And Swirl Mark Removal File in Section: 10 - Body Bulletin No. 53-17-04 Date: September, 1995 INFORMATION Subject: Polishing and Swirl Mark Removal Techniques for Basecoat/Clearcoat Paint Models: 1993-96 Passenger Cars and Trucks with Basecoat/Clearcoat This bulletin supersedes and cancels Corporate Bulletin Number 111702. Previous divisional publication numbers were: Buick 93-10-22 Cadillac T-93-104 Chevrolet 93-188-OB GM Canada 93-10-158 Oldsmobile 07-93-106 (Service Guild) Pontiac 93-10-28 Today's basecoat/clearcoat paint finishes are very different from materials used on vehicles in the 1980's. Materials, procedures and equipment which once worked well for polishing traditional finishes may not be acceptable for use on basecoat/clearcoat paint surfaces. The use of outdated materials, procedures and equipment may produce what appears to be acceptable results under shop lighting, but will be unacceptable to the owner when the finish is exposed to sunlight (typically, swirl marks). While the following information can be most helpful in the new car "prep" area, it should also be made available to the "used car" area and the collision/ paint repair area. KEEP THE VEHICLE CLEAN AND DRY; ^ Avoid washing vehicles in direct sunlight. ^ Avoid using strong soaps or chemical detergents. ^ Use "brush less" type automatic car wash equipment. ^ Avoid using products containing acids (unless specified to correct a condition such as "rail dust"). ^ Don't use brushes or brooms to remove snow or ice from vehicles in storage or on lots. ^ Cleaning agents and water should be dried promptly and not allowed to dry on the surface. ^ Standing rinse water should be dried promptly and not allowed to dry on the surface. ^ Drying with a soft chamois is recommended. DON'T CREATE A PROBLEM: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 531704 > Sep > 95 > Paint - Polishing And Swirl Mark Removal > Page 8755 ^ DO NOT polish vehicles unless a surface condition exists that can only be corrected by polishing (see chart). ^ If a surface condition does exist, the repair approach should be one of "less is best" (the very least it takes to correct the condition). ^ Avoid removing too much clearcoat (whenever possible, use paint gauges before, during, and after polishing). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Technical Service Bulletins for Paint: > 531704 > Sep > 95 > Paint - Polishing And Swirl Mark Removal > Page 8756 ^ Use ONLY the products recommended in this bulletin (or their equivalent). ^ Make sure that any power polishing equipment does not exceed the requirements in the polish manufacturer's recommendation or in the chart. FINAL STEP: The final step of the finesse/polish procedure is the removal of SWIRL MARKS. Swirl marks are defined as very fine scratches in a uniform circular direction that cause an optical distortion on the paint surface. Swirl marks may not be visible with shop lighting. They should be viewed in direct sunlight or under specific lights, i.e. Sodium Vapor (parking lot type lights). SWIRL MARK REMOVAL - To remove swirl marks, use an orbital polisher (DA) with speeds in the 1,500 to 2,000 RPM range. Apply a small amount of the appropriate material (see chart) to the swirl mark area. Use the pad on the random orbital buffer to spread the material evenly over polished area before buffing. When buffing, keep pad flat and constantly moving over the repair area. Polish with heavier pressure applied for 4-6 seconds, then polish with lighter pressure for 6-8 more seconds. Always blend or feather outer edges of repair spot. After buffing, the buffed areas should be inspected by the buffing person to ensure that the swirls are completely removed. If swirls are still present, rebuff as needed. Hand wipe the surface with a clean soft, non-scratching cloth and a 50/50 mixture of Isopropyl Alcohol and water. ^ DON'T USE WAX OR SILICONE-TYPE PRODUCTS TO HIDE SWIRL MARKS (this condition will reappear later and cause owner dissatisfaction). ^ Specific conditions on paint (environmental damage, rail dust, etc.) can be corrected by referring to previously published Service bulletins on those specific topics. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules Wiring Harness: All Technical Service Bulletins Electrical - MIL ON/DTC's Set By Various Control Modules TECHNICAL Bulletin No.: 09-06-03-004D Date: December 08, 2010 Subject: Intermittent No Crank/No Start, No Module Communication, MIL, Warning Lights, Vehicle Messages or DTCs Set by Various Control Modules - Diagnosing and Repairing Fretting Corrosion (Disconnect Affected Connector and Apply Dielectric Lubricant) Models: 2011 and Prior GM Passenger Cars and Trucks Attention: This repair can be applied to ANY electrical connection including, but not limited to: lighting, body electrical, in-line connections, powertrain control sensors, etc. DO NOT over apply lubricant to the point where it prevents the full engagement of sealed connectors. A light coating on the terminal surfaces is sufficient to correct the condition. Supercede: This bulletin is being revised to update the Attention statement and add the 2011 model year. Please discard Corporate Bulletin Number 09-06-03-004C (Section 06 Engine/Propulsion System). Condition Some customers may comment on any of the following conditions: - An intermittent no crank/no start - Intermittent malfunction indicator lamp (MIL) illumination - Intermittent service lamp illumination - Intermittent service message(s) being displayed The technician may determine that he is unable to duplicate the intermittent condition. Cause This condition may be caused by a buildup of nonconductive insulating oxidized debris known as fretting corrosion, occurring between two electrical contact surfaces of the connection or connector. This may be caused by any of the following conditions: - Vibration - Thermal cycling - Poor connection/terminal retention - Micro motion - A connector, component or wiring harness not properly secured resulting in movement On low current signal circuits this condition may cause high resistance, resulting in intermittent connections. On high current power circuits this condition may cause permanent increases in the resistance and may cause a device to become inoperative. Representative List of Control Modules and Components The following is only a representative list of control modules and components that may be affected by this connection or connector condition and DOES NOT include every possible module or component for every vehicle. - Blower Control Module - Body Control Module (BCM) - Communication Interface Module (CIM) - Cooling Fan Control Module - Electronic Brake Control Module (EBCM) - Electronic Brake and Traction Control Module (EBTCM) - Electronic Suspension Control (ESC) Module - Engine Control Module (ECM) - Heating, Ventilation and Air Conditioning (HVAC) Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8762 - HVAC Actuator - Inflatable Restraint Sensing and Diagnostic Module (SDM) - Any AIR BAG module - Seatbelt Lap Anchor Pretensioner - Seatbelt Retractor Pretensioner - An SIR system connection or connector condition resulting in the following DTCs being set: B0015, B0016, B0019, B0020, B0022, or B0023 - Powertrain Control Module (PCM) - Remote Control Door Lock Receiver (RCDLR) - Transmission Control Module (TCM) Correction Important DO NOT replace the control module, wiring or component for the following conditions: - The condition is intermittent and cannot be duplicated. - The condition is present and by disconnecting and reconnecting the connector the condition can no longer be duplicated. Use the following procedure to correct the conditions listed above. 1. Install a scan tool and perform the Diagnostic System Check - Vehicle. Retrieve and record any existing history or current DTCs from all of the control modules (refer to SI). ‹› If any DTC(s) are set, refer to Diagnostic Trouble Code (DTC) List - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). ‹› If DTCs are not set, refer to Symptoms - Vehicle to identify the connector(s) of the control module/component which may be causing the condition (refer to SI). 2. When identified, use the appropriate DTC Diagnostics, Symptoms, Schematics, Component Connector End Views and Component Locator documents to locate and disconnect the affected harness connector(s) which are causing the condition. Note Fretting corrosion looks like little dark smudges on electrical terminals and appear where the actual electrical contact is being made. In less severe cases it may be unable to be seen or identified without the use of a magnifying glass. Important DO NOT apply an excessive amount of dielectric lubricant to the connectors as shown, as hydrolock may result when attempting to mate the connectors. Use ONLY a clean nylon brush that is dedicated to the repair of the conditions in this bulletin. 3. With a one-inch nylon bristle brush, apply dielectric lubricant to both the module/component side and the harness side of the affected connector(s). 4. Reconnect the affected connector(s) and wipe away any excess lubricant that may be present. 5. Attempt to duplicate the condition by using the following information: - DTC Diagnostic Procedure - Circuit/System Description - Conditions for Running the DTC - Conditions for Setting the DTC - Diagnostic Aids - Circuit/System Verification ‹› If the condition cannot be duplicated, the repair is complete. ‹› If the condition can be duplicated, then follow the appropriate DTC, Symptom or Circuit/System Testing procedure (refer to SI). Repair Order Documentation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8763 Important The following information MUST be documented on the repair order. Failure to do so may result in a chargeback. - Customer vehicle condition. - Was a Service Lamp or Service Message illuminated? If yes, specify which Service Lamp or Service Message. - Was a DTC(s) set? If yes, specify which DTC(s) were set. - After following the procedure contained within this bulletin, could the condition be duplicated? ‹› If the condition was not duplicated, then document the affected module/component connector name and number on the repair order. - If the condition was duplicated after the procedure contained within this bulletin was followed, and additional diagnosis led to the replacement of a module or component, the SI Document ID Number MUST be written on the repair order. Parts Information Alternate Distributor For All of North America Note NyoGel(R) 760G Lubricant* is equivalent to GMSPO P/N 12377900, and P/N 10953529 (Canada), specified for use to correct the condition in this bulletin. *We believe this source and their products to be reliable. There may be additional manufacturers of such products/materials. General Motors does not endorse, indicate any preference for, or assume any responsibility for the products or material from this firm or for any such items that may be available from other sources. Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 09-06-03-004D > Dec > 10 > Electrical - MIL ON/DTC's Set By Various Control Modules > Page 8764 For vehicles repaired under warranty, use the appropriate/closest labor operation depending upon the module/component connection that the dielectric lubricant was applied to refer to the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair Wiring Harness: All Technical Service Bulletins Electrical - Information For Electrical Ground Repair INFORMATION Bulletin No.: 10-08-45-001B Date: October 25, 2010 Subject: Information for Electrical Ground Repair - Use New Replacement Fasteners with Conductive Finish Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add the 2011 model year and update the Warranty Information. Please discard Corporate Bulletin Number 10-08-45-001A (Section 08 - Body and Accessories). Electrical Ground Repair Overview Proper electrical system function relies on secure, stable and corrosion-free electrical ground connections. Loose, stripped, or corroded connections increase the possibility of improper system function and loss of module communication. These conditions may also lead to unnecessary repairs and component replacement. In general, electrical ground connections are accomplished using one, or a combination of the following attachment methods: - Welded M6 stud and nut - Welded M6 nut and bolt - Welded M8 nut and bolt Determine which attachment method is used and perform the appropriate or alternative repair as described in this bulletin. M6 Weld Stud Replacement Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. Select a location adjacent the damaged or missing M6 ground stud having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 3. Drill a 10 mm (0.40 in) diameter hole through the panel. 4. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 8769 Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 5. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 6. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 7. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 8. Ensure the rivet stud is securely fastened, WITHOUT ANY detectable movement. 9. Completely wrap the threads of the rivet stud with painters tape or equivalent. Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 10. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 11. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 12. Remove the painters tape or equivalent from the rivet stud threads. 13. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 14. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 8770 15. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 16. Install the electrical ground wire terminal to the rivet stud. 17. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 18. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in). 19. Verify proper system operation. M6 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M6 weld nut at the electrical ground location is damaged or stripped, a M7 conductive self-threading bolt may be used to secure the ground wire terminal. 2. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the weld nut and allow to dry. 3. Remove any loose metal particles from the damaged or stripped weld nut with a stiff brush. 4. Select a M7 conductive self-threading bolt. Refer to the Parts Information section of this bulletin 5. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M7 conductive self-threading bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 6. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 7. Install the electrical ground wire terminal to the M7 conductive self-threading bolt. 8. Install the M7 conductive self-threading bolt and: Tighten Tighten to 9 Nm (80 lb in). 9. Verify proper system operation. M6 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the electrical ground location is accessible from both sides of the panel, a M6 conductive bolt and a M6 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the damaged M6 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 8.5 mm (0.33 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 8.5 mm (0.33 in) hole until bare metal is visible. 6. Select a M6 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M6 conductive bolt to the ground location. 10. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M6 conductive nut to the bolt and: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 8771 Tighten Tighten to 8 Nm (71 lb in). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is accessible from both sides of the panel, a M8 conductive bolt and a M8 conductive nut may be used to secure the electrical ground wire terminal. Refer to the Parts Information section of this bulletin. 2. Select a location adjacent the M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the new electrical ground site. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the surface surrounding the ground location and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) hole until bare metal is visible. 6. Select a M8 conductive bolt. Refer to the Parts Information section of this bulletin. 7. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M8 conductive bolt. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 8. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 9. Install the electrical ground wire terminal and the M8 conductive bolt to the ground location. 10. Select a M8 conductive nut. Refer to the Parts Information section of this bulletin. 11. Install the M8 conductive nut to the bolt and: Tighten Tighten to 22 Nm (16 lb ft). Note The repair area MUST BE properly refinished to maintain a secure, stable and corrosion-free electrical ground. 12. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 13. Verify proper system operation. M8 Weld Nut Alternative Repair Caution Use only the GM-approved replacement fasteners with conductive finish for electrical ground repair. 1. If the M8 weld nut electrical ground location is not accessible from both sides of the panel, a M6 conductive rivet stud and a M6 conductive nut may be used to secure the electrical ground wire terminal. 2. Select a location adjacent the damaged M8 weld nut having 20 mm (0.79 in) clearance behind the panel surface and 20 mm (0.79 in) clearance surrounding the M6 conductive rivet stud flange. 3. Using GM approved residue-free solvent or equivalent, remove any grease from the repair site and allow to dry. Note Ensure 20 mm (0.79 in) clearance is maintained behind the panel to be drilled. 4. Drill a 10 mm (0.40 in) diameter hole through the panel. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 8772 5. Remove paint and primer from the area surrounding the 10 mm (0.40 in) until bare metal is visible. Important The M6 conductive rivet stud as shown, can accommodate a panel thickness range of 0.7-4.2 mm (0.03-0.17 in). If there are layers of sheet metal, they should be touching without any air gaps to ensure a good ground. 6. Select a M6 conductive rivet stud. Refer to the Parts Information section of this bulletin. Note Use the GE-50317 rivet stud tool kit. 7. Place the M6 conductive rivet stud (1) in the 10 mm (0.40 in) hole. Assemble the rivet stud tool (2) with the groove and flare side facing the rivet stud, then the washer and the M6 nut (3). 8. Using a wrench on the rivet stud tool, and a socket on the M6 nut, secure the M6 conductive rivet stud. 9. Ensure the new rivet stud is securely fastened, WITHOUT ANY detectable movement. 10. Completely wrap the threads of the rivet stud with painters tape or equivalent. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 8773 Note The rivet stud and surrounding panel area MUST BE properly refinished PRIOR to the installation of the electrical ground wire terminal and conductive nut to maintain a secure, stable and corrosion-free electrical ground. 11. Refinish the repair area using an anti-corrosion primer. Refer to Anti-Corrosion Treatment and Repair in SI. 12. Allow the refinished repair area to cure sufficiently before removing the protective material applied to the rivet stud threads. 13. Remove the painters tape or equivalent from the rivet stud threads. 14. Using GM approved residue-free solvent or equivalent, thoroughly clean the rivet stud threads to remove any adhesive and allow to dry. 15. Using a small brush, apply Dielectric Lubricant GM P/N 12377900 (Canadian P/N 10953529) to the threads of the M6 conductive rivet stud. Note Fretting corrosion is a build-up of insulating, oxidized wear debris that can form when there is a small motion between electrical contacts. The oxidized wear debris can accumulate at the electrical contact points causing the electrical resistance across the connection to increase. 16. Carefully remove ANY corrosion or contamination that may be present on the electrical ground wire terminal. 17. Install the electrical ground wire terminal to the M6 conductive rivet stud. 18. Select a M6 conductive nut. Refer to the Parts Information section of this bulletin. 19. Install the M6 conductive nut to the rivet stud and: Tighten Tighten to 8 Nm (71 lb in) 20. Verify proper system operation. Parts Information Warranty Information (excluding Saab Models) For vehicles repaired under warranty, use: Warranty Information (Saab Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 10-08-45-001B > Oct > 10 > Electrical - Information For Electrical Ground Repair > Page 8774 For vehicles repaired under warranty, use the table. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair Wiring Harness: All Technical Service Bulletins Electrical - Instrument Panel & General Wiring Repair Bulletin No.: 06-08-45-004 Date: May 02, 2006 INFORMATION Subject: Instrument Panel (I/P), Body and General Wiring Harness Repair Models: 2007 and Prior GM Cars and Trucks 2003-2007 HUMMER H2 2006-2007 HUMMER H3 Important: A part restriction has been implemented on all Body and I/P harnesses and is being administered by the PQC. If a body or I/P harness replacement is required, it can take 12-28 weeks for a harness to be built and delivered to a dealer. The dealer technician is expected to repair any harness damage as the first and best choice before replacing a harness. In an effort to standardize repair practices, General Motors is requiring that all wiring harnesses be repaired instead of replaced. If there is a question concerning which connector and/or terminal you are working on, refer to the information in the appropriate Connector End Views in SI. The Instruction Manual J 38125-620, which is sent with each new update of the J 38125 Terminal Repair Kit, also has terminal crimping and terminal remove information. Important: There are some parts in the J 38125 Terminal Repair Kit (i.e. SIR connector CPAs and heat shrink tube (used in high heat area pigtail replacement) and some TPAs that are not available from GMSPO. It is vitally important that each update to the J 38125 Terminal Repair Kit be done as soon as it arrives at the dealer. Utilize the Terminal Repair Kit (J 38125) to achieve an effective wiring repair. The Terminal Repair Kit has been an essential tool for all GM Dealers since 1987. Replacement terminals and tools for this kit are available through SPX/Kent Moore. Refer to Corporate Bulletin Number 06-08-45-001 for more information. The Instruction Manual J 38125-620, which is sent with each new update to the J 38125 Terminal Repair Kit, also has terminal crimping and terminal removal information. U.S. Dealers Only - Training courses (including Tech Assists, Emerging Issues, Web, IDL and Hands-on) are available through the GM Training website. Refer to Resources and then Training Materials for a complete list of available courses. Canadian Dealers Only - Refer to the Training section of GM infoNet for a complete list of available courses and a copy of the J 38125 Terminal Repair Kit Instruction Manual. Wiring repair information is also available in Service Information (SI). The Wiring Repair section contains information for the following types of wiring repairs: - Testing for intermittent conditions and poor conditions - Flat wire repairs - GMLAN wiring repairs - High temperature wiring repairs - Splicing copper wire using splice clips - Splicing copper wire using splice sleeves - Splicing twisted or shielded cable - Splicing inline harness diodes Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > 06-08-45-004 > May > 06 > Electrical - Instrument Panel & General Wiring Repair > Page 8779 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > Page 8780 Paint: By Symptom Technical Service Bulletin # 05-08-51-008C Date: 090622 Body - Bumps or Rust Colored Spots in Paint TECHNICAL Bulletin No.: 05-08-51-008C Date: June 22, 2009 Subject: Bumps or Rust Colored Spots in Paint Due to Rail or Iron Dust (Remove Rail Dust) Models: 1994-2010 GM Passenger Cars and Trucks (Including Saturn) 2003-2010 HUMMER H2 2006-2010 HUMMER H3 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 05-08-51-008B (Section 08 - Body and Accessories). Condition Visible rust colored spots or bumps on a vehicle's paint surface from rail or iron dust. Cause Rail dust comes from tiny iron particles produced from the friction between train wheels and the tracks and gets deposited on the vehicle surfaces. Iron dust can get deposited on the surface if the vehicle is stored near any operation producing iron dust such as an iron ore yard. Either material can lay on top of, or become embedded in, the paint surface. Correction Because the severity of the condition varies, proper diagnosis of the damage is critical to the success of repairs. Diagnosis should be performed on horizontal surfaces (hood, roof, deck lid, pick up box, etc.) after the vehicle has been properly cleaned. There are two types of repair materials recommended to repair rail dust or iron dust: 1. GEL TYPE OXALIC ACID: - Has the characteristics of the liquid type oxalic acid but stays where you put it because of its gel consistency. 2. CLAY TYPE NON-ACID BASED: - Requires surface lubricant during use. - Has different grades available. Caution Rail dust remover (Oxalic Acid) is an acidic substance containing chemicals that will break down the iron particles embedded in the finish. When working with rail dust remover, use the necessary safety equipment, including gloves and goggles. Follow the chemical manufacturer's directions closely because it may require special handling and disposal. If, upon inspection, some particles are still present, the various chemical manufacturer's processes can be repeated. After the removal process, small pits may remain in the clearcoat and can be corrected, in most cases, with a finesse/polish operation. Procedure 1. Move the vehicle to a cool shaded area and make sure that the vehicle surfaces are cool during the removal process. DO NOT PERFORM THE REMOVAL PROCESS IN DIRECT SUNLIGHT OR ON A VEHICLE WITH HOT OR WARM BODY PANELS. 2. Wash the vehicle with soap and water. Dry it immediately and clean the affected areas with a wax and grease remover. 3. Perform the removal process according to the chemical manufacturer's directions. Once the damage has been repaired, the final step involves a polishing process. Rail Dust Remover Manufacturers Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > Page 8781 Use the chemical manufacturers listed below, or equivalent: Auto Magic(R) or Clay Magic(R) products available from: Auto Wax Company, Inc. 1275 Round Table Dr. Dallas, TX 75247 (800) 826-0828 (Toll-Free) or (214) 631-4000 (Local) Fax (214) 634-1342 www.automagic.com [email protected] E038 Fallout Gel or E038E Liquid Fallout Remover II available from: Valvoline Car Brite Company 1910 South State Avenue Indianapolis, In 46203 (800) 347-2439 (Toll Free) or (317) 788-9925 (Local) Fax (317) 788-9930 www.carbrite.com [email protected] *We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources. If rail dust remover is not available in your area, call one of the numbers listed above for a distributor near your location. Warranty Information (excluding Saab U.S. Models) Important Refer to the Policy & Procedures Manual, section 1.2.1.7 for detailed information regarding warranty coverage for this condition. Important In certain cases where the vehicle finish is severely damaged and the actual repair time exceeds the published time, the additional time should be submitted in the "Other Labor Hours" field. Warranty Information (Saab U.S. Models) Disclaimer Technical Service Bulletin # 33-17-01A Date: 971201 Exhaust System - Paint Peeling from Painted Muffler Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > Page 8782 File In Section: 10 - Body Bulletin No.: 33-17-01A Date: December, 1997 Subject: Paint Peeling from Muffler (New Repair Paint Available) Models: 1993-98 Passenger Cars with Painted Mufflers This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 33-17-01 (Section 10 - Body). Condition Some owners may experience paint peeling from the muffler. Correction Clean and repaint the affected area using the following procedure and product. Important: DO NOT REPLACE COMPONENTS TO REPAIR THIS CONDITION. The exhaust system must be cold to begin this procedure. Material Required: * Wabash Products # KB-318-HHHS, available in pints or quarts as ready to spray material (no mixing required). Call Wabash Products, 1-800-326-7269 or 812-232-6097 for pricing and shipping information. Procedure On a cold exhaust system: 1. Raise vehicle on hoist. 2. While supporting exhaust with a transmission jack, remove the rear exhaust system hangers and lower the exhaust. 3. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 4. Wire brush the affected area to remove flaking paint and blow off with air. 5. Sand the affected area with # 80 to 150 grit sandpaper to remove rust, dirt or other contaminants. 6. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 7. Tape off the rear lower body panels and exhaust pipes forward of mufflers to protect from overspray. 8. Apply paint to affected area in several (6 to 8) thin coats (to prevent sags and runs) obtaining approximately 1 mil paint coverage. 9. Raise exhaust system with jack, reinstall exhaust hangers, lower vehicle and remove from hoist. ^ Allow 30 minutes drying time. 10. In a well ventilated area, start engine and allow to idle for up to 30 minutes until paint is cured and dry. Important: Some "smoking" will occur while curing the paint with the engine running. The paint can be heated and cured while driving, but be careful not to get the exhaust system wet during the first 30 minutes. Warranty Information Labor Material Operation Labor Time Allowance Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > Page 8783 A6150 0.6 hr - Single Exhaust GC Add 0.2 hr - Dual Exhaust GC Important: While the above procedure and materials are correct for vehicles from 1993 to 1998, the Labor Operation and Time Allowance only pertains to vehicles in the Warranty period. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Technical Service Bulletin # 05-08-51-008C Date: 090622 Body - Bumps or Rust Colored Spots in Paint TECHNICAL Bulletin No.: 05-08-51-008C Date: June 22, 2009 Subject: Bumps or Rust Colored Spots in Paint Due to Rail or Iron Dust (Remove Rail Dust) Models: 1994-2010 GM Passenger Cars and Trucks (Including Saturn) 2003-2010 HUMMER H2 2006-2010 HUMMER H3 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 05-08-51-008B (Section 08 - Body and Accessories). Condition Visible rust colored spots or bumps on a vehicle's paint surface from rail or iron dust. Cause Rail dust comes from tiny iron particles produced from the friction between train wheels and the tracks and gets deposited on the vehicle surfaces. Iron dust can get deposited on the surface if the vehicle is stored near any operation producing iron dust such as an iron ore yard. Either material can lay on top of, or become embedded in, the paint surface. Correction Because the severity of the condition varies, proper diagnosis of the damage is critical to the success of repairs. Diagnosis should be performed on horizontal surfaces (hood, roof, deck lid, pick up box, etc.) after the vehicle has been properly cleaned. There are two types of repair materials recommended to repair rail dust or iron dust: 1. GEL TYPE OXALIC ACID: - Has the characteristics of the liquid type oxalic acid but stays where you put it because of its gel consistency. 2. CLAY TYPE NON-ACID BASED: - Requires surface lubricant during use. - Has different grades available. Caution Rail dust remover (Oxalic Acid) is an acidic substance containing chemicals that will break down the iron particles embedded in the finish. When working with rail dust remover, use the necessary safety equipment, including gloves and goggles. Follow the chemical manufacturer's directions closely because it may require special handling and disposal. If, upon inspection, some particles are still present, the various chemical manufacturer's processes can be repeated. After the removal process, small pits may remain in the clearcoat and can be corrected, in most cases, with a finesse/polish operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > Page 8784 Procedure 1. Move the vehicle to a cool shaded area and make sure that the vehicle surfaces are cool during the removal process. DO NOT PERFORM THE REMOVAL PROCESS IN DIRECT SUNLIGHT OR ON A VEHICLE WITH HOT OR WARM BODY PANELS. 2. Wash the vehicle with soap and water. Dry it immediately and clean the affected areas with a wax and grease remover. 3. Perform the removal process according to the chemical manufacturer's directions. Once the damage has been repaired, the final step involves a polishing process. Rail Dust Remover Manufacturers Use the chemical manufacturers listed below, or equivalent: Auto Magic(R) or Clay Magic(R) products available from: Auto Wax Company, Inc. 1275 Round Table Dr. Dallas, TX 75247 (800) 826-0828 (Toll-Free) or (214) 631-4000 (Local) Fax (214) 634-1342 www.automagic.com [email protected] E038 Fallout Gel or E038E Liquid Fallout Remover II available from: Valvoline Car Brite Company 1910 South State Avenue Indianapolis, In 46203 (800) 347-2439 (Toll Free) or (317) 788-9925 (Local) Fax (317) 788-9930 www.carbrite.com [email protected] *We believe these sources and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from these firms or for any such items which may be available from other sources. If rail dust remover is not available in your area, call one of the numbers listed above for a distributor near your location. Warranty Information (excluding Saab U.S. Models) Important Refer to the Policy & Procedures Manual, section 1.2.1.7 for detailed information regarding warranty coverage for this condition. Important In certain cases where the vehicle finish is severely damaged and the actual repair time exceeds the published time, the additional time should be submitted in the "Other Labor Hours" field. Warranty Information (Saab U.S. Models) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > Page 8785 Disclaimer Technical Service Bulletin # 33-17-01A Date: 971201 Exhaust System - Paint Peeling from Painted Muffler File In Section: 10 - Body Bulletin No.: 33-17-01A Date: December, 1997 Subject: Paint Peeling from Muffler (New Repair Paint Available) Models: 1993-98 Passenger Cars with Painted Mufflers This bulletin is being revised to add additional model years. Please discard Corporate Bulletin Number 33-17-01 (Section 10 - Body). Condition Some owners may experience paint peeling from the muffler. Correction Clean and repaint the affected area using the following procedure and product. Important: DO NOT REPLACE COMPONENTS TO REPAIR THIS CONDITION. The exhaust system must be cold to begin this procedure. Material Required: * Wabash Products # KB-318-HHHS, available in pints or quarts as ready to spray material (no mixing required). Call Wabash Products, 1-800-326-7269 or 812-232-6097 for pricing and shipping information. Procedure On a cold exhaust system: 1. Raise vehicle on hoist. 2. While supporting exhaust with a transmission jack, remove the rear exhaust system hangers and lower the exhaust. 3. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 4. Wire brush the affected area to remove flaking paint and blow off with air. 5. Sand the affected area with # 80 to 150 grit sandpaper to remove rust, dirt or other contaminants. 6. Clean the affected area with a wax and grease remover, lacquer thinner or other suitable solvent. 7. Tape off the rear lower body panels and exhaust pipes forward of mufflers to protect from overspray. 8. Apply paint to affected area in several (6 to 8) thin coats (to prevent sags and runs) obtaining approximately 1 mil paint coverage. 9. Raise exhaust system with jack, reinstall exhaust hangers, lower vehicle and remove from hoist. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Paint, Striping and Decals > Paint > System Information > Technical Service Bulletins > All Other Service Bulletins for Paint: > Page 8786 ^ Allow 30 minutes drying time. 10. In a well ventilated area, start engine and allow to idle for up to 30 minutes until paint is cured and dry. Important: Some "smoking" will occur while curing the paint with the engine running. The paint can be heated and cured while driving, but be careful not to get the exhaust system wet during the first 30 minutes. Warranty Information Labor Material Operation Labor Time Allowance A6150 0.6 hr - Single Exhaust GC Add 0.2 hr - Dual Exhaust GC Important: While the above procedure and materials are correct for vehicles from 1993 to 1998, the Labor Operation and Time Allowance only pertains to vehicles in the Warranty period. * We believe this source and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Memory Positioning Module > Component Information > Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Power Door Lock Relay > Component Information > Locations Power Door Lock Relay: Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Power Door Lock Relay > Component Information > Locations > Page 8794 Base Of LH A Pillar With Power Door Locks Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Power Door Lock Relay > Component Information > Locations > Page 8795 Power Door Lock Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Power Seat Control Module > Component Information > Locations > Driver Seat Adjuster Memory Module Power Seat Control Module: Locations Driver Seat Adjuster Memory Module Below Center Of Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Power Seat Control Module > Component Information > Locations > Driver Seat Adjuster Memory Module > Page 8800 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Seat Heater Control Module > Component Information > Locations > Driver Seat Heater Control Module Seat Heater Control Module: Locations Driver Seat Heater Control Module Attached to seat support, under LH Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Seat Heater Control Module > Component Information > Locations > Driver Seat Heater Control Module > Page 8805 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Relays and Modules - Body and Frame > Trunk / Liftgate Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Head Restraint System > System Information > Technical Service Bulletins > Restraints - Driver/Passenger Seat Head Rest Information Head Restraint System: Technical Service Bulletins Restraints - Driver/Passenger Seat Head Rest Information INFORMATION Bulletin No.: 10-08-50-003A Date: March 24, 2011 Subject: Information on Driver or Passenger Seat Head Restraint Concerns with Comfort, Custom Upholstery or Other Comfort Enhancing Devices Models: 2012 and Prior GM Passenger Cars and Trucks Equipped with Adjustable Head Restraints Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 10-08-50-003 (Section 08 - Body and Accessories). Important ON A GM VEHICLE EQUIPPED WITH ADJUSTABLE HEAD RESTRAINTS, USE THE HEAD RESTRAINT COVERS, FOAM AND OTHER SEAT-RELATED EQUIPMENT AS RELEASED BY GM FOR THAT VEHICLE. DO NOT ALTER OR REPOSITION THE HEAD RESTRAINT SYSTEM. ANY ALTERATIONS TO HEAD RESTRAINTS DEFEATS THE INTENDED DESIGN OF THE SYSTEM. GM WILL NOT BE LIABLE FOR ANY PROBLEMS CAUSED BY USE OF SUCH IMPROPER DESIGN ALTERATIONS, INCLUDING ANY WARRANTY REPAIRS INCURRED. You may have a customer with a concern that the head restraint is uncomfortable or sits too far forward. The front driver and passenger seats are equipped with head restraints that have been designed to help minimize injuries while still providing comfort to the occupants. Each GM vehicle has its own specifically designed head restraint. The head restraints should only be used in the vehicle for which they were designed. The head restraint will not operate to its design intent if the original foam is replaced (1) by non-GM foam or head restraint, (2) by GM foam or head restraint designed for a different vehicle, (3) by GM foam or head restraint that has been altered by a trim shop or (4) if any object, such as an aftermarket comfort enhancing pad or device, is installed. Never modify the design of the head restraint or remove the head restraint from the vehicle as this may interfere with the operation of the seating and restraint systems and may prevent proper positioning of the passenger within the vehicle. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Memory Positioning Systems > Memory Positioning Module > Component Information > Locations Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Memory Positioning Systems > Seat Memory Switch > Component Information > Locations Seat Memory Switch: Locations LH Front door on armrest Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Control Module > Component Information > Locations > Driver Seat Adjuster Memory Module Power Seat Control Module: Locations Driver Seat Adjuster Memory Module Below Center Of Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Control Module > Component Information > Locations > Driver Seat Adjuster Memory Module > Page 8825 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Motor > Component Information > Locations > Driver FWD/Back Motor Power Seat Motor: Locations Driver FWD/Back Motor Under Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Motor > Component Information > Locations > Driver FWD/Back Motor > Page 8830 Power Seat Motor: Locations Driver Height Seat Motor Front Under Driver Seat Rear Under Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Motor > Component Information > Locations > Driver FWD/Back Motor > Page 8831 Power Seat Motor: Locations Driver Seatback Lumbar Support Motor Part of Driver Seat bottom Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Motor > Component Information > Locations > Driver FWD/Back Motor > Page 8832 Power Seat Motor: Locations Passenger FWD/Back Motor Under Passenger Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Motor > Component Information > Locations > Driver FWD/Back Motor > Page 8833 Power Seat Motor: Locations Driver FWD/Back Motor Under Driver Seat Front Under Driver Seat Rear Under Driver Seat Driver Seatback Lumbar Support Motor Part of Driver Seat bottom Passenger FWD/Back Motor Under Passenger Seat Front Under Passenger Seat Rear Under Passenger Seat Passenger Seatback Lumbar Support Motor Part of Passenger Seat bottom Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Motor > Component Information > Locations > Driver FWD/Back Motor > Page 8834 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Motor > Component Information > Locations > Driver FWD/Back Motor > Page 8835 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Switch > Component Information > Locations > Component Locations Power Seat Switch: Component Locations Driver Seat Switch Pod Bottom Of driver Seat, outboard Side Passenger Seat Switch Pod Part of bottom Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Switch > Component Information > Locations > Component Locations > Page 8840 Power Seat Switch: Connector Locations RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Switch > Component Information > Locations > Component Locations > Page 8841 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Switch > Component Information > Diagrams > LH and RH Lumbar Switch Assembly C312 & C313: LH And RH Lumbar Switch Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Power Seat Switch > Component Information > Diagrams > LH and RH Lumbar Switch Assembly > Page 8844 Power Seat Switch LH And RH Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Cover > Component Information > Technical Service Bulletins > Interior - Seat Cover Wrinkle/Crease/Burn Info Seat Cover: Technical Service Bulletins Interior - Seat Cover Wrinkle/Crease/Burn Info INFORMATION Bulletin No.: 04-08-50-006D Date: September 09, 2010 Subject: Minor Wrinkles/Creases, Discoloration, Cigarette Burns and Customer Induced Cuts and Stains on Front and Rear Driver and Passenger Seats with Leather, Vinyl or Cloth Seat Covers Models: 2011 and Prior GM Passenger Cars and Light Duty Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2009 and Prior Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add a model year. Please discard Corporate Bulletin Number 04-08-50-006C (Section 08 - Body and Accessories). If a customer comes in to your dealership due to certain conditions of the seat covers (splits, wrinkles, loose stitching, etc.), you must examine the seat cover in order to determine the validity of the customer claim. Some components from the above listed vehicles have been returned to the Warranty Parts Center (WPC) and analysis of these parts showed "customer induced damage" or No Trouble Found (NTF). The dealer should pay particular attention to the following conditions: - Cigarette burns Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Cover > Component Information > Technical Service Bulletins > Interior - Seat Cover Wrinkle/Crease/Burn Info > Page 8849 - Customer induced cuts (knife cuts, cut by customer tools, etc.) - Paint stains (customer should have cleaned paint stains while paint was still wet) - Coffee stains and other removable dirt These should be cleaned as described in the Owner's Manual under Appearance Care. Also, refer to Corporate Bulletin Number 06-00-89-029A or later. - Evidence of chemicals used for cleaning, other than those specified in the Owner's Manual - Other chemical spills - Minor and normal leather wrinkles as a result of use - Other defects to the seat cover not detected during the pre-delivery inspection (PDI). Inform the customer that the above issues were not present when the vehicle was purchased and cannot be replaced under warranty. The covers, however, may be repaired or replaced at the customer's expense. The following conditions are not caused by the customer and should be covered by warranty: - Split seams Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Cover > Component Information > Technical Service Bulletins > Interior - Seat Cover Wrinkle/Crease/Burn Info > Page 8850 - Wear/cracking/peeling - Discoloration/dye transfer from customer clothing (if discoloration/dye transfer is not removed after using GM Leather and Vinyl Plastic Cleaner, P/N 88861401 (in Canada, P/N 88861409), replace the covers.) Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Cover > Component Information > Technical Service Bulletins > Interior - Seat Cover Wrinkle/Crease/Burn Info > Page 8851 Seat Cover: Technical Service Bulletins Interior - Elimination Of Unwanted Odors INFORMATION Bulletin No.: 00-00-89-027E Date: September 29, 2008 Subject: Eliminating Unwanted Odors in Vehicles Models: 2009 and Prior GM Passenger Cars and Trucks (including Saturn) 2009 and Prior HUMMER H2, H3 Vehicles 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years and refine the instructions. Please discard Corporate Bulletin Number 00-00-89-027D (Section 00 - General Information). Vehicle Odor Elimination General Motors offers a product that may control or eliminate odors in the interior and luggage compartment areas of GM vehicles. GM Vehicle Care Odor Eliminator is a non-toxic, biodegradable odor remover. This odorless product has been shown to greatly reduce or remove objectionable smells of mold and mildew resulting from vehicle water leaks (as well as customer created odors, i.e. smoke). You may use GM Vehicle Care Odor Eliminator on fabrics, vinyl, leather, carpet and sound deadening materials. It may also be induced into HVAC modules and instrument panel ducts (for the control of non-bacterial related odors). Important: This product leaves no residual scent and should not be sold as or considered an air freshener. Product action may result in the permanent elimination of an odor and may be preferable to customers with allergies who are sensitive to perfumes. How to Use This Product GM Vehicle Care Odor Eliminator may be sprayed on in a ready-to-use formula or used in steam cleaners as an additive with carpet shampoo. This water-based, odorless product is safe for all vehicle interiors. Do not wet or soak any interior surface that plain water would cause to deteriorate, as this product will have the same effect. Also avoid letting this product come into contact with vinegar or any acidic substance. Acid-based products will hamper the effectiveness of, or render GM Vehicle Care Odor Eliminator inert. Note: Complete eight page treatment sheets are enclosed within each case of GM Vehicle Care Odor Eliminator. These treatment instructions range from simple vehicle odor elimination to full step by step procedures for odor removal from water leaks. If lost, contact 800-977-4145 to get a replacement set faxed or e-mailed to your dealership. Instructions and cautions are printed on the bottle, but additional help is available. If you encounter a difficult to eliminate or reoccurring odor, you may call 1-800-955-8591 (in Canada, 1-800-977-4145) to obtain additional information and usage suggestions. Important: This product may effectively remove odors when directly contacting the odor source. It should be used in conjunction with diagnostic procedures (in cases such as a water leak) to first eliminate the root cause of the odor, and then the residual odor to permanently correct the vehicle condition. Vehicle Waterleak Odor Elimination STEP ONE: Confirm that all water leaks have been repaired. Determine what areas of the vehicle were water soaked or wet. Components with visible mold/mildew staining should be replaced. Isolate the odor source inside the vehicle. Often an odor can be isolated to an area or component of the vehicle interior by careful evaluation. Odor evaluation may need to be performed by multiple persons. Another method of isolating an odor source is to remove and segregate interior trim and components. Plastic sheeting or drop cloths can be used to confine seats, headliners, etc. to assist in evaluation and diagnoses. If appropriate the vehicle and interior trim should be evaluated separately to determine if the odor stays with the vehicle or the interior components. Odors that stay with the vehicle may be isolated to insulating and sound deadening materials (i.e. water leak at the windshield or standing water in the front foot well area caused mold/mildew to form on the bulkhead or kick panel sound deadening pads. If the interior is removed the floor pan and primed/painted surfaces should be treated with bleach/soap solution, rinsed with clean water and dried. Interior surfaces should then be treated with GM Vehicle Care Odor Eliminator product before reinstalling carpet or reassembling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Cover > Component Information > Technical Service Bulletins > Interior - Seat Cover Wrinkle/Crease/Burn Info > Page 8852 The GM Vehicle Care Odor Eliminator product is an effective odor elimination product when used properly. It must come into direct contact with the odor source. It should be used in conjunction with diagnostic procedures to first eliminate the root cause of the odor. Some procedures for use after odor root cause correction are: STEP TWO: ^ Use the trigger spray head. ^ Put a drop of dish soap the size of a quarter in the bottom of a bottle. ^ Add 8 oz. of GM Vehicle Care Odor Eliminator (1 cup) to the dish soap and top off the bottle with tap water. ^ This formula should be used on hard surfaces (dash, interior plastic molding, and floor pan) STEP THREE: The third step to neutralizing the vehicle is a light to medium treatment of all carpeting and upholstered seats with the GM Vehicle Care Odor Eliminator formula and a wide fan spray setting (at full strength) (i.e.: carpeting on the driver's side requires 4-5 triggers pulls for coverage). The headliner and trunk should be sprayed next. Lightly brushing the formula into the carpeting and upholstery is a recommended step for deep odor problems. The dash and all hard surfaces should be sprayed with dish soap/water mixture. Let stand for 1-2 minutes then wipe off the surface. STEP FOUR: (vehicle ventilation system treatment) The ventilation system is generally the last step in the treatment of the vehicle. a. Spray the GM Vehicle Care Odor Eliminator formula into all dash vents. (1-2 trigger pulls per vent). b. Start the vehicle and turn the vehicle fan on high cool (not A/C setting). c. Spray the formula (10 trigger pulls) into the outside fresh air intake vent (cowl at base of windshield) d. Enter the vehicle after 1 minute and wipe off the excess formula spurting out of the dash vents. e. Smell the air coming from the dash vents. If odors are still present, spray another 5 triggers into the cowl, wait another minute and smell the results. Once you have obtained a fresh, clean smell coming from the vents, turn the system to the A/C re-circulation setting. Roll up the windows, spray 3-5 pumps into the right lower IP area and let the vehicle run with the fan set on high for 5-7 minutes. Please follow this diagnosis process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the remaining steps do not need to be performed. If these steps do not resolve the condition, please contact GM TAC for further diagnostic assistance. Additional Suggestions to Increase Customer Satisfaction Here are some additional ideas to benefit your dealership and to generate greater customer enthusiasm for this product. ^ Keep this product on-hand for both the Service Department and the Used Car lot. Add value to your used car trades; treat loaner and demo cars during service and at final sale to eliminate smoke, pet, and other common odors offensive to customers. Make deodorizing a vehicle part of your normal vehicle detailing service. ^ Consider including GM Vehicle Care Odor Eliminator as a give-away item with new vehicle purchases. Many dealers give away as "gifts" various cleaning supplies at time of delivery. GM Odor Eliminator is one of a few products GM offers that has as many uses in the home as in the vehicle. Customers may find this product can be used for a host of recreational activities associated with their new vehicle, such as deodorizing a boat they tow, or a camper. ^ GM Odor Eliminator and many of the GM Vehicle Care products offer you the chance to increase dealership traffic as these superior quality products cannot be purchased in stores. Many Dealerships have product displays at the parts counter. Consider additional displays in the Customer Service Lounge, the Showroom and at the Service Desk or Cashier Window. Many customers who purchase vehicles and receive regular maintenance at your dealership may never visit the parts counter, and subsequently are not exposed to the variety and value that these products offer. Parts Information Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Cover > Component Information > Technical Service Bulletins > Interior - Seat Cover Wrinkle/Crease/Burn Info > Page 8853 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Cover > Component Information > Technical Service Bulletins > Interior - Seat Cover Wrinkle/Crease/Burn Info > Page 8854 Seat Cover: Technical Service Bulletins Leather Seat Covers - Cleaning Procedure File In Section: 10 - Body Bulletin No.: 43-16-06 Date: October, 1994 Subject: Cleaning Procedure for Leather Seat Covers Models: 1995 and Prior Passenger Cars and "C/K" and "S/T" Trucks If leather seat covers are being returned only because they are dirty, a more aggressive cleaning procedure is recommended by General Motors prior to replacing covers. Procedure Dirty or soiled leather seat covers should be cleaned with a mild soap and water solution, using clean soft cloths. When this procedure proves inadequate, a commercially available leather cleaner, "Tanner's Preserve Leather Cleaner"* should be used with a 3M "Type T"* scrubbing pad. Important: The type of scrubbing pad is very critical because the common 3M Scotch-Brite green pad is too aggressive and will damage the leather finish. The cleaner is available from "First Brands" by calling 1-800-726-1001, identifying yourself as a GM dealership, requesting "Tanner's Preserve Leather Cleaner" product, number AS-330, quantity and shipping address. This product is also available at stores. The 3M "Type T" scrubbing pad is available from a 3M distributor. Call 1-800-742-9546 for the nearest distributor and then request the Scotch-Brite Clean and Finish Sheet, "Type T", in 6 x 9 inch sheets, UPC code number 048011-01276. * We believe these sources and their equipment to be reliable. There may be additional manufacturers of such equipment. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or for any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Heater Control Module > Component Information > Locations > Driver Seat Heater Control Module Seat Heater Control Module: Locations Driver Seat Heater Control Module Attached to seat support, under LH Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Heater Control Module > Component Information > Locations > Driver Seat Heater Control Module > Page 8859 Underside Of Driver Seat, Passenger Seat Similar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Heater Switch > Component Information > Locations > Driver Seat Heater Switch Seat Heater Switch: Locations Driver Seat Heater Switch LH side of Driver's Seat Cushion Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Seats > Seat Heater Switch > Component Information > Locations > Driver Seat Heater Switch > Page 8864 Seat Heater Switch: Locations Passenger Seat Heater Switch LH side of Passenger Seat Cushion Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Component Locations Power Door Lock Switch: Component Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Component Locations > Page 8870 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Component Locations > Page 8871 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Door Lock Switch > Component Information > Locations > Page 8872 Power Door Lock Switch RH And LH Front Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Mirror Switch > Component Information > Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Locations > Component Locations Power Seat Switch: Component Locations Driver Seat Switch Pod Bottom Of driver Seat, outboard Side Passenger Seat Switch Pod Part of bottom Driver Seat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Locations > Component Locations > Page 8880 Power Seat Switch: Connector Locations RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Locations > Component Locations > Page 8881 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Diagrams > LH and RH Lumbar Switch Assembly C312 & C313: LH And RH Lumbar Switch Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Power Seat Switch > Component Information > Diagrams > LH and RH Lumbar Switch Assembly > Page 8884 Power Seat Switch LH And RH Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Seat Heater Switch > Component Information > Locations > Driver Seat Heater Switch Seat Heater Switch: Locations Driver Seat Heater Switch LH side of Driver's Seat Cushion Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Seat Heater Switch > Component Information > Locations > Driver Seat Heater Switch > Page 8889 Seat Heater Switch: Locations Passenger Seat Heater Switch LH side of Passenger Seat Cushion Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Seat Memory Switch > Component Information > Locations Seat Memory Switch: Locations LH Front door on armrest Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Component Locations Trunk / Liftgate Switch: Component Locations Trunk Lid With Pull-Down Back View Of LH Instrument Panel Rear Compartment Lid Enable Switch Mounted on I/P Compartment Rear Luggage Compartment With Pull-Down Rear Compartment Lid Pull-Down Striker Switch Attached to Rear Compartment Lid Pulldown Actuator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Component Locations > Page 8897 Rear Compartment Lid Pull-Down Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Component Locations > Page 8898 Trunk Lid With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Sensors and Switches - Body and Frame > Trunk / Liftgate Switch > Component Information > Locations > Page 8899 Rear Glass Interlock/Push Button Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Tailgate > Component Information > Diagrams Tailgate: Diagrams C406: Body Harness To Tailgate Harness, Headlamp Automatic Control Module (C1), Remote Control Door Lock Receiver C405: Body Harness To Tailgate Harness Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Body and Frame > Weatherstrip > Component Information > Technical Service Bulletins > Body - Maintaining Exterior Weatherstrip Appearance Weatherstrip: Technical Service Bulletins Body - Maintaining Exterior Weatherstrip Appearance INFORMATION Bulletin No.: 99-08-64-016C Date: July 29, 2009 Subject: Information on Maintaining Exterior Weatherstrip Appearance Models: 2010 and Prior Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years and update the parts and procedure information. Please discard Corporate Bulletin Number 99-08-64-016B (Section 08 - Body and Accessories). Exterior weatherstrips are exposed to a variety of environmental elements, including UV rays, acid rain, insect and bird residue and atmospheric fallout. All of these may effect the appearance of the weatherstrips; however, they do not effect the functionality of the weatherstrip. Weatherstrips that are discolored should not be replaced under the normal GM New Vehicle Warranty. Weatherstrip Maintenance Instructions Silicone grease on weatherstrips will make them last longer, seal better, and not stick or squeak. Clean the weatherstrips with a mild soap and water solution. Apply silicone grease with a clean cloth. During very cold, damp weather, frequent application may be required. Refer to the information below for the recommended maintenance products. Weatherstrips that are not maintained may crack and weather due to environmental elements. Parts Information Weatherstrip Conditioning Weatherstrip Lubricant (GM P/N 3634770 [in Canada, P/N 10953518]) or Dielectric Silicone Grease (GM P/N 12345579 [in Canada, P/N 992887]). Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Brake Switch (Cruise Control) > Component Information > Service and Repair Brake Switch (Cruise Control): Service and Repair Fig. 3 Cruise Control Release Switch & Stop Lamp Switch Assemblies 1. Disconnect electrical connectors, then remove release switch and stop lamp switch assemblies from retainers, Fig. 3. 2. Remove retainers from bracket. 3. Reverse procedure to install. Adjust as outlined. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Module > Component Information > Locations LH Rear Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Module > Component Information > Locations > Page 8914 Cruise Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Module > Component Information > Locations > Page 8915 Cruise Control Module: Description and Operation DESCRIPTION The module has an electronic controller and an electric stepper motor to vary the throttle with each different cruise mode. The module is not serviceable and must be replaced as an assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Module > Component Information > Locations > Page 8916 Cruise Control Module: Service and Repair Fig. 36 Cruise Control Module Removal 1. Disconnect battery ground cable. 2. Disconnect electrical connector from module, Fig. 36. 3. Disconnect cruise control cable from module, then remove bolts and screws. 4. Remove module and plugs. 5. Remove plugs from module if a new module is being installed. 6. Reverse procedure to install noting the following: a. Align holes in accelerator and cruise control adjuster bracket to holes in wheel house panel and position module on wheel house panel. b. Torque module bolts and screws to 71 ft. lbs. c. Adjust cable, if necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Servo Cable > Component Information > Adjustments Cruise Control Servo Cable: Adjustments 1. Remove air cleaner and resonator. 2. Unlock cable conduit at support bracket. 3. With throttle closed, lock cable conduit by pressing down on lock tab. 4. When cable is in unlocked position and throttle is closed, cable adjustment spring removes appropriate amount of slack. 5. Lock button must be fully extended to allow proper adjustment spring operation prior to locking. 6. Install air cleaner and resonator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Servo Cable > Component Information > Adjustments > Page 8920 Cruise Control Servo Cable: Service and Repair Fig. 30 Cruise Control Cable Retainer Removal. Fig. 31 Cruise Control Cable Removal The cable is connected between the cruise control module and throttle body lever. 1. Remove air cleaner and resonator. 2. Remove cable and conduit from engine bracket, Fig. 30. 3. Remove cable end fitting from throttle body lever stud. 4. Remove cruise control retainer at module. 5. Remove cable from module as follows: a. Compress conduit tangs, Fig. 31, and pull out of module housing. b. Disconnect cable bead from cruise motor band end fitting on module, Fig. 31. c. Note routing and remove cable. 6. Reverse procedure to install noting the following: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Servo Cable > Component Information > Adjustments > Page 8921 a. Ribbon must not be twisted, slide cable conduit fitting over ribbon and snap into module housing. Ensure both tangs are engaged. b. Adjust cable as outlined under Adjustments. See: Adjustments Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations > Page 8926 Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations > Page 8927 Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Switch > Component Information > Locations > Page 8928 C215: Cruise Control Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Switch > Component Information > Locations > Page 8929 Cruise Control Switch: Description and Operation Fig. 3 Cruise Control Release Switch & Stop Lamp Switch Assemblies DESCRIPTION The release switch and stop lamp switch cannot be adjusted until after the brake booster pushrod is assembled to brake pedal assembly. Refer to Fig. 3 when performing this procedure. OPERATION 1. Depress brake pedal and insert release switch and stop lamp switch assembly into retainers until fully seated. 2. Slowly release brake pedal back to its original position. Release switch and stop lamp switch assemblies will move within retainers to their adjusted position. 3. The following brake pedal travel distances can be used to check for properly adjusted release switch and stop lamp switch assemblies: a. Release switch and stop lamp switch assemblies contacts must be open at 1/8-1/2 inch brake pedal travel, measured at centerline of brake pedal pad. b. Nominal actuation of stop lamp switch contacts is about 3/16 inch after cruise switch control contacts close. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Cruise Control Switch > Component Information > Locations > Page 8930 Cruise Control Switch: Service and Repair The engagement switch is not serviceable. The complete turn signal, headlamp dimmer switch, cruise control actuator and windshield wiper/washer must be replaced as an assembly. 1. Disconnect battery ground cable. 2. Remove steering column access cover, then disconnect electrical connector. Ensure windshield wiper switch is in Off position. 3. Remove lever assembly by pulling straight out. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations LH Rear Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations > Page 8935 Cruise Control Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations > Page 8936 Cruise Control Module: Description and Operation DESCRIPTION The module has an electronic controller and an electric stepper motor to vary the throttle with each different cruise mode. The module is not serviceable and must be replaced as an assembly. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Relays and Modules - Cruise Control > Cruise Control Module > Component Information > Locations > Page 8937 Cruise Control Module: Service and Repair Fig. 36 Cruise Control Module Removal 1. Disconnect battery ground cable. 2. Disconnect electrical connector from module, Fig. 36. 3. Disconnect cruise control cable from module, then remove bolts and screws. 4. Remove module and plugs. 5. Remove plugs from module if a new module is being installed. 6. Reverse procedure to install noting the following: a. Align holes in accelerator and cruise control adjuster bracket to holes in wheel house panel and position module on wheel house panel. b. Torque module bolts and screws to 71 ft. lbs. c. Adjust cable, if necessary. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Brake Switch (Cruise Control) > Component Information > Service and Repair Brake Switch (Cruise Control): Service and Repair Fig. 3 Cruise Control Release Switch & Stop Lamp Switch Assemblies 1. Disconnect electrical connectors, then remove release switch and stop lamp switch assemblies from retainers, Fig. 3. 2. Remove retainers from bracket. 3. Reverse procedure to install. Adjust as outlined. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations > Page 8946 Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Component Locations > Page 8947 Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Page 8948 C215: Cruise Control Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Page 8949 Cruise Control Switch: Description and Operation Fig. 3 Cruise Control Release Switch & Stop Lamp Switch Assemblies DESCRIPTION The release switch and stop lamp switch cannot be adjusted until after the brake booster pushrod is assembled to brake pedal assembly. Refer to Fig. 3 when performing this procedure. OPERATION 1. Depress brake pedal and insert release switch and stop lamp switch assembly into retainers until fully seated. 2. Slowly release brake pedal back to its original position. Release switch and stop lamp switch assemblies will move within retainers to their adjusted position. 3. The following brake pedal travel distances can be used to check for properly adjusted release switch and stop lamp switch assemblies: a. Release switch and stop lamp switch assemblies contacts must be open at 1/8-1/2 inch brake pedal travel, measured at centerline of brake pedal pad. b. Nominal actuation of stop lamp switch contacts is about 3/16 inch after cruise switch control contacts close. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Cruise Control Switch > Component Information > Locations > Page 8950 Cruise Control Switch: Service and Repair The engagement switch is not serviceable. The complete turn signal, headlamp dimmer switch, cruise control actuator and windshield wiper/washer must be replaced as an assembly. 1. Disconnect battery ground cable. 2. Remove steering column access cover, then disconnect electrical connector. Ensure windshield wiper switch is in Off position. 3. Remove lever assembly by pulling straight out. 4. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Sensors and Switches - Cruise Control > Vehicle Speed Sensor/Transducer - Cruise Control > Component Information > Description and Operation Vehicle Speed Sensor/Transducer - Cruise Control: Description and Operation DESCRIPTION The Vehicle Speed Sensor (VSS) buffer receives a signal from the VSS (permanent magnet generator) indicating vehicle speed. The buffer processes the signal which is then sent to the Engine Control Module (ECM), cruise control module and speedometer. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Cruise Control > Vehicle Speed Sensor/Transducer - Cruise Control > Component Information > Description and Operation Vehicle Speed Sensor/Transducer - Cruise Control: Description and Operation DESCRIPTION The Vehicle Speed Sensor (VSS) buffer receives a signal from the VSS (permanent magnet generator) indicating vehicle speed. The buffer processes the signal which is then sent to the Engine Control Module (ECM), cruise control module and speedometer. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > ABS Light > Component Information > Description and Operation ABS Light: Description and Operation This lamp will be illuminated when the ignition switch is placed in the ON position. The lamp may be illuminated for as long as 30 seconds as a bulb and system check. If lamp remains illuminated or comes on while operating the vehicle, a problem in the anti-lock brake system is indicated. When lamp is illuminated, place ignition switch in OFF position, then restart engine. If lamp still remains illuminated, the anti-lock brake system should be serviced. The brake system will remain functional, but without the anti-lock function. After servicing the anti-lock brake system the lamp will automatically reset. On some models it may be necessary to operate vehicle at a speed over 18 mph to reset lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Air Conditioning Indicator Lamp > Component Information > Service and Repair Air Conditioning Indicator Lamp: Service and Repair This lamp will be illuminated when the A/C system detects a low refrigerant charge. The lamp will be illuminated for approximately 2 seconds after ignition switch has been placed in the On position as a bulb check. If while operating vehicle, the lamp illuminates for approximately 60 seconds and then goes off, the refrigerant level is low enough to cause reduced cooling capacity. At this point the blower motor will increase speed to try to offset the loss in cooling capacity. The lamp will be automatically reset after system has been checked and refrigerant charge has been brought to proper level. If lamp is illuminated for approximately 60 seconds after engine start up, the refrigerant charge may be low enough to cause A/C compressor damage. When this condition is encountered, the A/C compressor clutch is de-energized and the A/C system is switched from Auto to Econ. The system will remain in Econ until necessary repairs are made and system is recharged. After completing necessary repairs and recharging the system, A/C system operation will return to normal and the lamp will be automatically reset. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Ammeter Gauge > Component Information > Description and Operation Ammeter Gauge: Description and Operation DESCRIPTION The CS generator uses a new type of regulator which has a built in fault detection. The CS generator does not have a diode trio or test hole. This generator uses only two connections, battery positive and an "L" terminal to the charge indicator bulb. Use of " P", "F" and "S" terminals is optional. The "P" terminal is connected to the stator and may be connected to a tachometer or other device. The "F" terminal is connected internally to field positive and is used in service diagnostics. The "S" terminal may be connected externally to a voltage source, such as battery voltage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Ammeter Gauge > Component Information > Description and Operation > Page 8967 Ammeter Gauge: Testing and Inspection If charge indicator light works abnormally, perform the following test procedure: 1. Visually check belt and wiring. 2. With engine control switch ON and engine stopped, charge indicator lamp should be on. If lamp is not on, detach wiring harness at generator and ground "L" terminal. If lamp lights, generator is faulty. If lamp does not light, locate open circuit between grounding lead and ignition switch and check for a faulty bulb. 3. With engine control switch ON and engine running at a moderate speed, charge indicator lamp should be off. If lamp is not off, detach wiring harness at generator. If lamp goes off, generator is faulty. If lamp stays on, check for grounded "L" terminal in wire harness. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Locations > Seat Belt/Ignition Key/Lamps/Turn Signal Alarm Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Locations > Seat Belt/Ignition Key/Lamps/Turn Signal Alarm > Page 8972 LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions Audible Warning Device: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8975 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8976 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8977 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8978 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8979 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8980 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8981 Audible Warning Device: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8982 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8983 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8984 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8985 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8986 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8987 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8988 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8989 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8990 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8991 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8992 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8993 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8994 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8995 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8996 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8997 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8998 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 8999 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9000 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9001 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9002 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9003 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9004 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9005 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9006 Audible Warning Device: Electrical Diagrams Audible Warning (Part 1 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Diagrams > Diagram Information and Instructions > Page 9007 Audible Warning (Part 2 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Description and Operation > Courtesy Lamps Audible Warning Device: Description and Operation Courtesy Lamps When CKT 156 is pulled low because a door has been opened, the Alarm will ground CKT 1393. When CKT 1393 is pulled low, the relay contacts in the Dome Courtesy Relay will close, allowing CKT 149 to go low via CKT 450. CKT 149 is the ground side of the Courtesy Light System. CKT 149 can also be grounded at the Headlamp/Panel Dimmer Switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Description and Operation > Courtesy Lamps > Page 9010 Audible Warning Device: Description and Operation Fasten Seat Belt Warning The Alarm applies voltage to the Seat Belt Switch at all times. The Alarm senses a voltage drop at the Seat Belt Latch Signal through the closed contacts of the Seat Belt Switch when the driver's seat belt is unlatched. When the driver's seat belt is latched, the Seat Belt Switch is opened and the Alarm senses voltage at the Seat Belt Latch Signal. When the Ignition Switch is turned to "RUN," voltage is applied to the Alarm Ignition Signal. When voltage is present at the Ignition Signal and no voltage is present at the Seat Belt Latch Signal, the Alarm will, sound the Fasten Seat Belt Warning for about 5 to 8 seconds. If voltage is present at the Ignition Signal and the Seat Belt Latch Signal, the Alarm will disable the Fasten Seat Belt Warning Chime. When the Ignition Switch is turned to "RUN," the Alarm senses voltage at the Ignition Signal. When voltage is applied to the Ignition Signal, the Alarm applies voltage to the "FASTEN SEAT BELT" Indicator for 5 to 8 seconds independent of the Seat Belt Switch and Fasten Seat Belt Warning chime. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Description and Operation > Courtesy Lamps > Page 9011 Audible Warning Device: Description and Operation General Information The Seat Belt/Ignition Key/Lamps/Turn Signal Alarm generates three audible warnings which are: Lights "ON" Warning and Turn Signal "ON" Reminder, Ignition Key Warning and Fasten Seat Belt Warning. Each warning is a series of pulsed tones or chimes. The Lights "ON" Warning and Turn Signal "ON" Reminder are pulsed approximately every one half second, sounding the quickest. The Ignition Key Warning is pulsed once every second. The Fasten Seat Belt Warning is pulsed approximately once every 1 1/2 seconds, sounding the slowest. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Description and Operation > Courtesy Lamps > Page 9012 Audible Warning Device: Description and Operation Illuminated Entry When a door is opened and closed, the Courtesy Lamps will stay "ON" for 30-40 seconds unless the Ignition Switch is turned to the "RUN" position. Voltage on CKT 639 will cause the Courtesy Lamps to shut "OFF" immediately. If the vehicle (Buick only) is equipped with Keyless Entry (AUO), the RCDLR will ground CKT 1393 for 30-40 seconds, unless the Ignition Switch is in the "RUN" position. Refer to Keyless Entry Schematic Details. See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Remote Keyless Entry/Diagrams/Electrical Diagrams Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Description and Operation > Courtesy Lamps > Page 9013 Audible Warning Device: Description and Operation Courtesy Lamps When CKT 156 is pulled low because a door has been opened, the Alarm will ground CKT 1393. When CKT 1393 is pulled low, the relay contacts in the Dome Courtesy Relay will close, allowing CKT 149 to go low via CKT 450. CKT 149 is the ground side of the Courtesy Light System. CKT 149 can also be grounded at the Headlamp/Panel Dimmer Switch. Fasten Seat Belt Warning The Alarm applies voltage to the Seat Belt Switch at all times. The Alarm senses a voltage drop at the Seat Belt Latch Signal through the closed contacts of the Seat Belt Switch when the driver's seat belt is unlatched. When the driver's seat belt is latched, the Seat Belt Switch is opened and the Alarm senses voltage at the Seat Belt Latch Signal. When the Ignition Switch is turned to "RUN," voltage is applied to the Alarm Ignition Signal. When voltage is present at the Ignition Signal and no voltage is present at the Seat Belt Latch Signal, the Alarm will, sound the Fasten Seat Belt Warning for about 5 to 8 seconds. If voltage is present at the Ignition Signal and the Seat Belt Latch Signal, the Alarm will disable the Fasten Seat Belt Warning Chime. When the Ignition Switch is turned to "RUN," the Alarm senses voltage at the Ignition Signal. When voltage is applied to the Ignition Signal, the Alarm applies voltage to the "FASTEN SEAT BELT" Indicator for 5 to 8 seconds independent of the Seat Belt Switch and Fasten Seat Belt Warning chime. General Information The Seat Belt/Ignition Key/Lamps/Turn Signal Alarm generates three audible warnings which are: Lights "ON" Warning and Turn Signal "ON" Reminder, Ignition Key Warning and Fasten Seat Belt Warning. Each warning is a series of pulsed tones or chimes. The Lights "ON" Warning and Turn Signal "ON" Reminder are pulsed approximately every one half second, sounding the quickest. The Ignition Key Warning is pulsed once every second. The Fasten Seat Belt Warning is pulsed approximately once every 1 1/2 seconds, sounding the slowest. Illuminated Entry When a door is opened and closed, the Courtesy Lamps will stay "ON" for 30-40 seconds unless the Ignition Switch is turned to the "RUN" position. Voltage on CKT 639 will cause the Courtesy Lamps to shut "OFF" immediately. If the vehicle (Buick only) is equipped with Keyless Entry (AUO), the RCDLR will ground CKT 1393 for 30-40 seconds, unless the Ignition Switch is in the "RUN" position. Refer to Keyless Entry Schematic Details. See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Remote Keyless Entry/Diagrams/Electrical Diagrams Key-In-Ignition Warning The Alarm applies voltage at all times to the Ignition Key Alarm Switch. When the Ignition Key is placed into the Ignition Lock Cylinder, the Ignition Key Alarm Switch is closed. When the LH front door is open, the LH Front Door Jamb Switch closes the circuit to ground. The Alarm senses a voltage drop at the Ignition Key Signal and will sound the Ignition Key Warning. Lamps on Warning When the Headlamp Switch is in "PARK" or "HEAD", voltage is applied to the Lights "ON" Signal of the Alarm. When the Ignition Switch is turned out of the "RUN" position, voltage is removed from the Ignition Signal of the Alarm. When voltage is present at the Lights "ON" Signal and no voltage applied to the Ignition Signal, the Alarm will sound the Lights "ON" Warning. For non-T82 vehicles, the Lights "ON" Warning can be turned OFF by turning the Instrument Panel Dimmer Switch to the "OFF" position. Turn Signal on Reminder When a turn signal is operated, the Alarm begins to monitor the distance the vehicle has travelled. If a turn signal is still flashing after the vehicle has travelled 0.8 km (0.5 mile), the Alarm turns the Lights "ON" Warning on. The Lights "ON" Warning continues to sound until the turn signal is turned "OFF." Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures Audible Warning Device: Diagnostic Trouble Code Tests and Associated Procedures System Check System Diagnosis Perform the System Check in the order shown. When a fault is found, refer to the Symptom Table for the appropriate diagnostic procedure(s). If a normal result is found at each and every step of the System Check, the fault may be intermittent. See: System Check See: Symptom Related Diagnostic Procedures/Symptom Table To help isolate an intermittent fault first examine the mating terminals at each component and connector for a poor connection. Also check that each terminal of mating connectors is properly seated in the connector body. If the connections appear to be reliable, try the System Check again while moving the wiring harness from side to side at each component and in-line connector, to try and induce the intermittent fault. Once a fault has been corrected, perform the System Check to verify the diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures > Page 9016 Audible Warning Device: Symptom Related Diagnostic Procedures Chart #1 All Warning Alarms Inoperative Chart #2 Ignition Key Warning Inoperative Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures > Page 9017 Chart #3 FASTEN SEAT BELT Warning Inoperative Chart #4 FASTEN SEAT BELT Indicator ON Continuously Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures > Page 9018 Chart #5 FASTEN SEAT BELT Indicator Inoperative Chart #6 Turn Signal ON Reminder Inoperative Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures > Page 9019 Chart #7 Courtesy Lights Are Inoperative With DOOR(S) OPEN (Non-SEO) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures > Page 9020 Chart #8 Courtesy Lights Stay ON Continuously (Non-SEO) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures > Page 9021 Symptom Table (Part 1 Of 2) Symptom Table (Part 2 Of 2) Troubleshooting Hints PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: 1. Check I/P Fuse Block Fuse #33. If open, check for a short to ground in CKT 40. 2. Check I/P Fuse Block Fuse #13. If open, check for a short to ground in CKT 639. 3. Check I/P Fuse Block Fuse #12. If open, check for a short to ground in CKT 239. 4. Check that ground G200 is clean and tight. 5. If Speedometer or Cruise Control (if equipped) does not operate properly refer to "Vehicle Speed Sensor." See: Powertrain Management/Computers and Control Systems/Sensors and Switches - Computers and Control Systems/Vehicle Speed Sensor/Testing and Inspection/Symptom Related Diagnostic Procedures/Symptom Diagnostic Charts ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids ^ Refer to System Diagnosis. See: Diagnostic Trouble Code Tests and Associated Procedures/System Diagnosis Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Audible Warning Device > Component Information > Testing and Inspection > Diagnostic Trouble Code Tests and Associated Procedures > Page 9022 Audible Warning Device: Component Tests and General Diagnostics Courtesy Lamps When CKT 156 is pulled low because a door has been opened, the Alarm will ground CKT 1393. When CKT 1393 is pulled low, the relay contacts in the Dome Courtesy Relay will close, allowing CKT 149 to go low via CKT 450. CKT 149 is the ground side of the Courtesy Light System. CKT 149 can also be grounded at the Headlamp/Panel Dimmer Switch. Fasten Seat Belt Warning The Alarm applies voltage to the Seat Belt Switch at all times. The Alarm senses a voltage drop at the Seat Belt Latch Signal through the closed contacts of the Seat Belt Switch when the driver's seat belt is unlatched. When the driver's seat belt is latched, the Seat Belt Switch is opened and the Alarm senses voltage at the Seat Belt Latch Signal. When the Ignition Switch is turned to "RUN," voltage is applied to the Alarm Ignition Signal. When voltage is present at the Ignition Signal and no voltage is present at the Seat Belt Latch Signal, the Alarm will, sound the Fasten Seat Belt Warning for about 5 to 8 seconds. If voltage is present at the Ignition Signal and the Seat Belt Latch Signal, the Alarm will disable the Fasten Seat Belt Warning Chime. When the Ignition Switch is turned to "RUN," the Alarm senses voltage at the Ignition Signal. When voltage is applied to the Ignition Signal, the Alarm applies voltage to the "FASTEN SEAT BELT" Indicator for 5 to 8 seconds independent of the Seat Belt Switch and Fasten Seat Belt Warning chime. General Informations The Seat Belt/Ignition Key/Lamps/Turn Signal Alarm generates three audible warnings which are: Lights "ON" Warning and Turn Signal "ON" Reminder, Ignition Key Warning and Fasten Seat Belt Warning. Each warning is a series of pulsed tones or chimes. The Lights "ON" Warning and Turn Signal "ON" Reminder are pulsed approximately every one half second, sounding the quickest. The Ignition Key Warning is pulsed once every second. The Fasten Seat Belt Warning is pulsed approximately once every 1 1/2 seconds, sounding the slowest. Ignition Key Warning The Alarm applies voltage at all times to the Ignition Key Alarm Switch. When the Ignition Key is placed into the Ignition Lock Cylinder, the Ignition Key Alarm Switch is closed. When the LH front door is open, the LH Front Door Jamb Switch closes the circuit to ground. The Alarm senses a voltage drop at the Ignition Key Signal and will sound the Ignition Key Warning. Illuminated Entry When a door is opened and closed, the Courtesy Lamps will stay "ON" for 30-40 seconds unless the Ignition Switch is turned to the "RUN" position. Voltage on CKT 639 will cause the Courtesy Lamps to shut "OFF" immediately. If the vehicle (Buick only) is equipped with Keyless Entry (AUO), the RCDLR will ground CKT 1393 for 30-40 seconds, unless the Ignition Switch is in the "RUN" position. Refer to Keyless Entry Schematic Details. See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Remote Keyless Entry/Diagrams/Electrical Diagrams Lamps-ON Warning Alarm When the Headlamp Switch is in "PARK" or "HEAD", voltage is applied to the Lights "ON" Signal of the Alarm. When the Ignition Switch is turned out of the "RUN" position, voltage is removed from the Ignition Signal of the Alarm. When voltage is present at the Lights "ON" Signal and no voltage applied to the Ignition Signal, the Alarm will sound the Lights "ON" Warning. For non-T82 vehicles, the Lights "ON" Warning can be turned OFF by turning the Instrument Panel Dimmer Switch to the "OFF" position. Turn Signal on Reminder When a turn signal is operated, the Alarm begins to monitor the distance the vehicle has travelled. If a turn signal is still flashing after the vehicle has travelled 0.8 km (0.5 mile), the Alarm turns the Lights "ON" Warning on. The Lights "ON" Warning continues to sound until the turn signal is turned "OFF." Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions Brake Warning Indicator: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9027 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9028 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9029 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9030 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9031 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9032 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9033 Brake Warning Indicator: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9034 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9035 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9036 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9037 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9038 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9039 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9040 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9041 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9042 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9043 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9044 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9045 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9046 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9047 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9048 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9049 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9050 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9051 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9052 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9053 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9054 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9055 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9056 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9057 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Diagrams > Diagram Information and Instructions > Page 9058 Brake Warning System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Description and Operation > Brake Warning System Brake Warning Indicator: Description and Operation Brake Warning System DESCRIPTION The "Brake" warning indicator will be illuminated when a low brake fluid level in the master cylinder is sensed or when the Electronic Brake Control Module (EBCM) lights it in response to certain diagnostic trouble codes. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Description and Operation > Brake Warning System > Page 9061 Brake Warning Indicator: Description and Operation Circuit Operation Voltage is applied to the "BRAKE" Indicator from I/P Fuse #11 when the Ignition Switch is turned to "RUN," "BULB TEST" or "START." The "BRAKE" Indicator is controlled by any one of three switches: the Brake Pressure Switch, Ignition Switch or Park Brake Indicator Switch. When the Ignition Switch is turned to "BULB TEST" or "START," CKT 209 is grounded through the Ignition Switch to activate the "BRAKE" Indicator. When the Brake Pressure Switch is closed, CKT 209 is grounded through the contacts of the Brake Pressure Switch to activate the "BRAKE" Indicator. CKT 33 is grounded through the Park Brake Switch when the Park Brake is set, to activate the "BRAKE" Indicator. With the Daytime Running Lamps (DRL) Control Module grounded through CKT 33, the module provides ground to CKT 209, lighting the "BRAKE" Indicator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Description and Operation > Brake Warning System > Page 9062 Brake Warning Indicator: Description and Operation Brake Pressure Warning Lamp DESCRIPTION The warning lamp should illuminate when the ignition switch is in the start position, and turn off when the switch returns to run. If the brake lamp remains on after the ignition returns to run, check fluid level in master cylinder reservoir and inspect parking brake. If the warning lamp does not turn on during cranking, check for defective bulb or blown fuse. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Brake Warning Indicator: Initial Inspection and Diagnostic Overview Circuit Operation Voltage is applied to the "BRAKE" Indicator from I/P Fuse #11 when the Ignition Switch is turned to "RUN," "BULB TEST" or "START." The "BRAKE" Indicator is controlled by any one of three switches: the Brake Pressure Switch, Ignition Switch or Park Brake Indicator Switch. When the Ignition Switch is turned to "BULB TEST" or "START," CKT 209 is grounded through the Ignition Switch to activate the "BRAKE" Indicator. When the Brake Pressure Switch is closed, CKT 209 is grounded through the contacts of the Brake Pressure Switch to activate the "BRAKE" Indicator. CKT 33 is grounded through the Park Brake Switch when the Park Brake is set, to activate the "BRAKE" Indicator. With the Daytime Running Lamps (DRL) Control Module grounded through CKT 33, the module provides ground to CKT 209, lighting the "BRAKE" Indicator. System Diagnosis ^ Perform the System Check and refer to the Symptom Table for the appropriate diagnostic procedure(s). See: System Check See: Symptom Related Diagnostic Procedures/Symptom Table System Check Troubleshooting Hints PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: 1. Check I/P Fuse Block Fuse #11. If Fuse #11 is open check for a short to ground in CKT 39. 2. Check brake fluid level. If low, refer to Antilock Brake System. See: Brakes and Traction Control/Antilock Brakes / Traction Control Systems ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures."). See: Diagrams/Diagnostic Aids ^ Refer to System Diagnosis. See: System Diagnosis Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9065 Brake Warning Indicator: Symptom Related Diagnostic Procedures Symptom Table Chart #1 Ignition Switch Does Not Activate The BRAKE Indicator Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9066 Chart #2 Park Brake Does Not Activate The BRAKE Indicator (Base Or Twilight Sentinel) Chart #3 Park Brake Does Not Activate The BRAKE IND (With DRL) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9067 Chart #4 BRAKE IND Stay ON W/IGN SW In RUN & Park Brake Released (Base/Twilight Sentinel) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9068 Chart #4 BRAKE IND Stays ON W/IGN SW In RUN & Park Brake Released (W/DRL) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Brake Warning Indicator > Component Information > Testing and Inspection > Page 9069 Brake Warning Indicator: Service and Repair This lamp will be illuminated when the ignition switch is placed in the ON position. The lamp may be illuminated for as long as 30 seconds as a bulb and system check. If lamp remains illuminated or comes on while operating the vehicle, a problem in the anti-lock brake system is indicated. When lamp is illuminated, place ignition switch in OFF position, then restart engine. If lamp still remains illuminated, the anti-lock brake system should be serviced. The brake system will remain functional, but without the anti-lock function. After servicing the anti-lock brake system the lamp will automatically reset. On some models it may be necessary to operate vehicle at a speed over 18 mph to reset lamp. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Check Gauges Lamp > Component Information > Description and Operation Check Gauges Lamp: Description and Operation The "Check Gage" warning lamp will illuminate to warn the driver to check the oil pressure gauge, engine coolant temperature gauge and the voltmeter. When lit, the "Check Gage" lamp indicates that one of these gauges is operating in an abnormal range. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Cigarette Lighter > Component Information > Technical Service Bulletins > Customer Interest for Cigarette Lighter: > 99-08-45-005 > Nov > 99 > Accessory Receptacle/Cigar Lighter - Inoperative Cigarette Lighter: Customer Interest Accessory Receptacle/Cigar Lighter - Inoperative File In Section: 08 - Body and Accessories Bulletin No.: 99-08-45-005 Date: November, 1999 TECHNICAL Subject: Accessory Receptacle/Cigar Lighter is Inoperative (Check Aftermarket Device Plug for Short to Ground) Models: 1995-2000 Passenger Cars and Trucks Condition Some customers may comment that the cigar lighter or the accessory receptacle is inoperative; or that the internal fuse (within the plug on an aftermarket device), blows intermittently. Cause Certain aftermarket devices have a newly designed power plug with an internal mini fuse. The mini fuse may have an external terminal (which may be used to externally check the fuse). If the mini fuse external test terminal is not recessed into the mini fuse body, it may come in contact with the shell of the vehicle receptacle and cause the fuse (of either the vehicle or the aftermarket device), to blow intermittently. Correction Test the aftermarket device plug for short to ground. The following step may be performed at the customer's expense. As this is not a defect in material, design or workmanship of the vehicle, it would be the owner's responsibility. 1. Place a piece of tape over the mini fuse terminal temporarily. 2. Explain to the customer that the fuse for the device must have no exposed terminals, and that finding one would be his responsibility. 3. Refer the customer to the manufacturer of the aftermarket device for a new plug. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Cigarette Lighter > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Cigarette Lighter: > 99-08-45-005 > Nov > 99 > Accessory Receptacle/Cigar Lighter - Inoperative Cigarette Lighter: All Technical Service Bulletins Accessory Receptacle/Cigar Lighter - Inoperative File In Section: 08 - Body and Accessories Bulletin No.: 99-08-45-005 Date: November, 1999 TECHNICAL Subject: Accessory Receptacle/Cigar Lighter is Inoperative (Check Aftermarket Device Plug for Short to Ground) Models: 1995-2000 Passenger Cars and Trucks Condition Some customers may comment that the cigar lighter or the accessory receptacle is inoperative; or that the internal fuse (within the plug on an aftermarket device), blows intermittently. Cause Certain aftermarket devices have a newly designed power plug with an internal mini fuse. The mini fuse may have an external terminal (which may be used to externally check the fuse). If the mini fuse external test terminal is not recessed into the mini fuse body, it may come in contact with the shell of the vehicle receptacle and cause the fuse (of either the vehicle or the aftermarket device), to blow intermittently. Correction Test the aftermarket device plug for short to ground. The following step may be performed at the customer's expense. As this is not a defect in material, design or workmanship of the vehicle, it would be the owner's responsibility. 1. Place a piece of tape over the mini fuse terminal temporarily. 2. Explain to the customer that the fuse for the device must have no exposed terminals, and that finding one would be his responsibility. 3. Refer the customer to the manufacturer of the aftermarket device for a new plug. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Cigarette Lighter > Component Information > Technical Service Bulletins > Page 9086 Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Coolant Level Indicator Lamp > Component Information > Description and Operation Coolant Level Indicator Lamp: Description and Operation DESCRIPTION This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. OPERATION Some vehicles use a buzzer or indicator lamp to convey a low coolant level condition. The buzzer or lamp is activated by a sensor, located in the radiator, when the coolant level becomes one quart low, or more. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator Off W/Coolant Level Low Fig. 97 Chart 6: Low Coolant Level Indicator Inoperative W/Coolant Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Low Coolant Indicator Off W/Coolant Level Low > Page 9092 Coolant Level Indicator Lamp: Testing and Inspection Low Coolant Indicator On w/Coolant Level OK Fig. 96 Chart 5: Low Coolant Level Indicator On W/Coolant Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Coolant Level Indicator Lamp > Component Information > Testing and Inspection > Page 9093 Coolant Level Indicator Lamp: Service and Repair This lamp will be illuminated when engine coolant level in the radiator drops below a predetermined level. To turn lamp off, check cooling system, then add coolant to bring system to proper level. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Dash Board / Instrument Panel <--> [Dashboard / Instrument Panel] > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming Air Bag(s) Arming and Disarming: Service and Repair Air Bag Disarming and Arming Disabling the SIR System The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Ensure front wheels are pointed straight ahead. 2. Turn ignition switch to LOCK position and remove SIR or AIR BAG fuse. 3. Remove Connector Position Assurance (CPA), then disconnect both yellow 2-way SIR electrical connectors at base of steering column. 4. Wait at least 2 minutes before proceeding with diagnosis or service. Enabling the SIR System 1. Connect both 2-way yellow connectors at base of steering column. 2. Install Connector Position Assurance (CPA). 3. Install SIR or AIR BAG fuse into fuse block. 4. Turn ignition to the RUN position and ensure that the "Inflatable Restraint lamp flashes seven to nine times and then turns off. If lamp does not operate as specified, refer to Testing And Inspection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Dash Board / Instrument Panel <--> [Dashboard / Instrument Panel] > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming > Page 9099 Air Bag(s) Arming and Disarming: Service and Repair General Service Precautions CAUTION; When performing service on or around SIR components or SIR wiring, follow the procedures to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Dimmer Switch > Component Information > Technical Service Bulletins > IP Dimmer Control - Proper Setting Dimmer Switch: Technical Service Bulletins IP Dimmer Control - Proper Setting File In Section: 08 - Body and Accessories Bulletin No.: 99-08-42-009 Date: November, 1999 INFORMATION Subject: Proper Setting of I/P Dimmer Control to View PRNDL Display with Automatic Headlamp Control Models: 2000 and Prior All Passenger Cars and Trucks With Automatic Headlamp Control and Electronic PRNDL Display Under certain conditions, if the instrument panel dimmer control is turned relatively low, the PRNDL will not be visible until the automatic headlamp control turns the headlamps off and the daytime running lamps (DRL) are turned back on. Such a condition may be if the vehicle is first started in an environment where the headlamp control turns on the headlamps and then the vehicle is driven out into a brighter environment (for example, when a vehicle is backed out of a dark garage into the bright sunlight). This condition is normal and any repair attempt will not be successful. Demonstrate this condition to the customer using the service lane and then turn the instrument panel dimmer control to a higher setting. This will enable the driver to see the PRNDL display Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Dimmer Switch > Component Information > Locations > Component Locations Dimmer Switch: Component Locations Lower LH Side Of Steering Column Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Dimmer Switch > Component Information > Locations > Component Locations > Page 9106 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Dimmer Switch > Component Information > Locations > Page 9107 Dimmer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Dimmer Switch > Component Information > Locations > Page 9108 Dimmer Switch: Service and Repair Fig. 13 Column Mounted Dimmer Switch Installation 1. Disconnect battery ground cable. 2. Remove instrument panel lower trim and on models with A/C, remove A/C duct extension at column. 3. Disconnect shift indicator from column and remove toe-plate cover screws. 4. Remove two nuts from instrument panel support bracket studs and lower steering column, resting steering wheel on front seat. 5. Remove dimmer switch retaining screws, then the switch. Tape actuator rod to column and separate switch from rod. 6. Reverse procedure to install. To adjust switch, depress dimmer switch slightly and install a 3/32 inch twist drill to lock switch to the body, Fig. 13. Force switch upward to remove lash between switch and pivot, then remove tape from actuator rod. Remove twist drill and check for proper operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door/Trunk Ajar Indicator/Lamp > Component Information > Locations Door/Trunk Ajar Indicator/Lamp: Locations LH Side of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door/Trunk Ajar Indicator/Lamp > Component Information > Testing and Inspection > Gate Ajar Indicator Inop Door/Trunk Ajar Indicator/Lamp: Testing and Inspection Gate Ajar Indicator Inop Fig. 100 Chart 9: Gate Ajar Indicator Inoperative Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door/Trunk Ajar Indicator/Lamp > Component Information > Testing and Inspection > Gate Ajar Indicator Inop > Page 9114 Door/Trunk Ajar Indicator/Lamp: Testing and Inspection Gate Ajar Indicator on at All Times Fig. 101 Chart 10: Gate Ajar Indicator On At All Times Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9119 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9120 Door Switch: Locations Door Jamb Switch, RH Front Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9121 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9122 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge > Component Information > Description and Operation > Fuel Gauge System Fuel Gauge: Description and Operation Fuel Gauge System DESCRIPTION The fuel gauge system consists of a sending unit, instrument voltage regulator and an electric fuel gauge. The sending unit is a variable resistor that is controlled by a float. Corresponding to actual fuel level, the float will rise or fall. When the ignition is turned to the On position, voltage is applied to the gauge through the voltage regulator, completing the gauge ground circuit through the sending unit. OPERATION When the tank is full and the float is raised, maximum resistance (approximately 90 ohms) is produced by the sending unit, current flow through the gauge is decreased, and the gauge pointer moves slightly. As the tank empties and the float drops resistance in the sending unit decreases, current flow through the gauge increases and the gauge pointer moves toward empty. Most analog fuel gauges are of the free floating type, which means that the gauge pointer does not remain against the full stop when the ignition is off. Rather, the pointer floats to a mid-position when no voltage is applied to the gauge. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge > Component Information > Description and Operation > Fuel Gauge System > Page 9127 Fuel Gauge: Description and Operation Fuel Usage DESCRIPTION This system consists of green and amber indicator lights located on the fuel gauge or telltale lamp cluster, a switch mounted on the instrument panel behind the gauges and an interconnecting vacuum hose and tee. OPERATION The system operates on engine vacuum through a dual contact vacuum sensing switch. When the accelerator is operated slowly and smoothly, engine vacuum remains high and the switch passes current to the green indicator light which indicates economical fuel consumption. When the accelerator pedal is depressed rapidly, vacuum decreases and the switch passes current to the amber indicator light, which indicates high fuel consumption. The amber indicator light will glow when the ignition switch is in the On position with the engine stopped. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge > Component Information > Testing and Inspection > Symptom Related Diagnostic Procedures Fuel Gauge: Symptom Related Diagnostic Procedures Fuel Gauge Inaccurate Tester BT-6508 or equivalent must be used to diagnose dash gauge malfunction. 1. Ensure battery is fully charged, disconnect electrical connector to tank unit and connect tester to between harness connector and suitable ground following manufacturer's instructions. 2. Set tester on empty then turn on ignition. Gauge should read empty or below. 3. Set tester on full. Gauge should read full or above. 4. If gauge does not respond to tester input, replace dash gauge. If gauge responds correctly, check for poor connections at tank unit, poor tank unit ground or defective tank unit. Fuel Gauge Is Inaccurate or Inoperative Fig. 103 Chart 1: Fuel Gauge Inoperative Or Inaccurate (Part 1 Of 2) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge > Component Information > Testing and Inspection > Symptom Related Diagnostic Procedures > Page 9130 Fig. 103 Chart 1: Fuel Gauge Inoperative Or Inaccurate (Part 2 Of 2) Gauge Reads Empty When Tank Is Full This condition is generally caused by a short in the fuel tank unit circuit. 1. Disconnect electrical connector to sending unit, then turn ignition switch to ON position. 2. If gauge reads past full, test gauge with tester tool No. BT-6508, or equivalent. If gauge reads empty, disconnect main body harness connector, Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge > Component Information > Testing and Inspection > Symptom Related Diagnostic Procedures > Page 9131 near the fuse block. 3. If gauge still shows empty, check for short in printed circuit or defective gauge. If gauge reads beyond full, reconnect front body harness connector and disconnect rear body harness connector (in left wheel house). 4. If gauge shows empty, locate and repair grounded wire in harness between front and rear body harness connectors. If gauge reads beyond full, check for short between rear body harness connector, damaged float or defective sending unit. Gauge Reads Full or Beyond at All Times This condition is generally caused by an open in the tank unit circuit. 1. Check tank unit ground for proper contact with body or chassis and repair as needed. 2. If tank unit ground is satisfactory, disconnect electrical connector to tank unit and connect harness side of connector to suitable ground with jumper wire, then turn on ignition. 3. If gauge reads empty, remove fuel tank and inspect wiring to sending unit. If wiring and connections are satisfactory, replace tank unit. 4. If gauge still shows full, disconnect front body harness connector and ground fuel gauge wire terminal in instrument panel side of connector. 5. If gauge still reads full, check for loose connection in cluster, open (crack) in printed circuit or defective gauge. If gauge reads empty, locate and repair open or poor connection between front body connector and tank unit connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge > Component Information > Testing and Inspection > Symptom Related Diagnostic Procedures > Page 9132 Fuel Gauge: Component Tests and General Diagnostics 1. With ignition switch in the on position, ground each terminal at the economy switch. Both green and amber indicator lights should glow. If not check for burned out bulbs. 2. With ignition switch in On position, amber indicator light should glow. If not, check for loose or disconnected wires at fuel economy switch or for poor ground. If amber indicator light still does not glow replace switch. 3. Start engine and allow to idle, the green indicator light should glow. If not, check for leaking, plugged or kinked vacuum hose between vacuum source and fuel economy switch. Check for loose or disconnected wires at economy switch or poor ground. If green indicator lamp still does not glow, replace switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge Sender > Component Information > Locations Fuel Gauge Sender: Locations Mounted on Fuel Tank, Part of Fuel Tank Unit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Fuel Gauge Sender > Component Information > Locations > Page 9136 Fuel Pump/Sender Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Locations > Heads Up Display (HUD) Projector Heads Up Display Unit: Locations Heads Up Display (HUD) Projector Customer Installed Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Locations > Heads Up Display (HUD) Projector > Page 9141 Heads Up Display Unit: Locations Night Vision Control Unit Customer Installed Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Locations > Heads Up Display (HUD) Projector > Page 9142 Heads Up Display Unit: Locations Night Vision Roof Unit Exterior of Roof Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions Heads Up Display Unit: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9145 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9146 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9147 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9148 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9149 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9150 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9151 Heads Up Display Unit: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9152 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9153 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9154 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9155 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9156 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9157 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9158 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9159 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9160 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9161 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9162 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9163 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9164 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9165 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9166 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9167 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9168 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9169 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9170 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9171 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9172 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9173 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9174 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9175 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9176 Heads Up Display Unit: Electrical Diagrams Heads Up Display (HUD): (HUD) Special Equipment Option Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9177 Heads Up Display (HUD): Night Vision (SEO) (UV1) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Heads Up Display Unit > Component Information > Diagrams > Diagram Information and Instructions > Page 9178 Heads Up Display (HUD): Night Vision (SEO) (UV3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Instrument Cluster / Carrier <--> [Instrument Cluster / Carrier] > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming Air Bag(s) Arming and Disarming: Service and Repair Air Bag Disarming and Arming Disabling the SIR System The diagnostic energy reserve module or sensing and diagnostic module (DERM/SDM) can maintain enough voltage to cause air bag deployment for up to two minutes after the ignition switch is turned off and the battery is disconnected. Servicing the SIR system during this period may result in accidental deployment and personal injury. 1. Ensure front wheels are pointed straight ahead. 2. Turn ignition switch to LOCK position and remove SIR or AIR BAG fuse. 3. Remove Connector Position Assurance (CPA), then disconnect both yellow 2-way SIR electrical connectors at base of steering column. 4. Wait at least 2 minutes before proceeding with diagnosis or service. Enabling the SIR System 1. Connect both 2-way yellow connectors at base of steering column. 2. Install Connector Position Assurance (CPA). 3. Install SIR or AIR BAG fuse into fuse block. 4. Turn ignition to the RUN position and ensure that the "Inflatable Restraint lamp flashes seven to nine times and then turns off. If lamp does not operate as specified, refer to Testing And Inspection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Instrument Cluster / Carrier <--> [Instrument Cluster / Carrier] > Air Bag(s) Arming and Disarming > System Information > Service and Repair > Air Bag Disarming and Arming > Page 9184 Air Bag(s) Arming and Disarming: Service and Repair General Service Precautions CAUTION; When performing service on or around SIR components or SIR wiring, follow the procedures to temporarily disable the SIR system. Failure to follow procedures could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repair. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Instrument Cluster / Carrier <--> [Instrument Cluster / Carrier] > Instrument Panel Bulb > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Low Fuel Lamp/Indicator > Component Information > Description and Operation Low Fuel Lamp/Indicator: Description and Operation DESCRIPTION The switch type consists of an indicator light and a low fuel warning switch located on the instrument panel. OPERATION The warning switch contacts are closed by the difference in voltage potential between the fuel gauge terminals. This voltage differential will activate the warning switch when the fuel tank is less than 1/4 full and, in turn, cause the indicator to light. This system incorporates an indicator light. With ignition switch turned to On, the indicator should light. If not, check bulb and all electrical connections. Replace warning switch if bulb and connections prove satisfactory. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions Malfunction Indicator Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9195 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9196 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9197 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9198 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9199 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9200 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9201 Malfunction Indicator Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9202 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9203 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9204 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9205 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9206 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9207 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9208 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9209 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9210 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9211 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9212 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9213 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9214 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9215 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9216 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9217 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9218 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9219 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9220 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9221 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9222 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9223 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9224 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Malfunction Indicator Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9225 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Odometer > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations Odometer: Technical Service Bulletins Odometer/Speedometer - ACDelco Service Center Locations File In Section: 8 - Chassis/Body Electrical Bulletin No.: 66-83-04A Date: September, 1996 INFORMATION Subject: AC Delco Service Center Locations for Odometer/Speedometer Service Models: 1997 and Prior Passenger Cars and Trucks (excluding Cadillac) This bulletin is being revised to provide the necessary contact information only. Please discard Corporate Bulletin Number 66-83-04 (Section 8 - Chassis/Body Electrical) General Motors provides service for sophisticated electronic products through the authorized AC Delco Service Center Program. This program is designed to provide GM vehicle owners with the highest quality and most technically up-to-date product available. Repair products from unauthorized service outlets are not acceptable as warranty replacements. Currently, there are 25 authorized AC Delco Service Centers who exchange and remanufacture odometer/speedometers (list included). Only these Centers should be contacted for service. Important: W series and 1997 T series Medium Duty truck odometer/speedometers must be ordered directly from GMSPO. The following steps should be taken when utilizing the AC Delco Service Centers: Dealers should contact their local AC Delco Service Center (list included). Any listed facility may be used. The following information must be provided: Part number VIN, Mileage, Vehicle Year, Make and Model Dealer Name and Address Delivery Date of Vehicle Name of the person requesting exchange or service Phone number Repair Order Number P.O. number (if non - warranty) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Odometer > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations > Page 9230 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Odometer > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations > Page 9231 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Odometer > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations > Page 9232 AC Delco Service Centers Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Change Reminder Lamp > Component Information > Service and Repair > Change Oil or Change Oil Now Message Oil Change Reminder Lamp: Service and Repair Change Oil or Change Oil Now Message 1. Turn ignition switch to On position, without starting engine. 2. Press accelerator pedal to wide open throttle (WOT) position and release three times within five seconds. 3. If Change Oil warning indicator goes out, system has been reset. 4. If Change Oil warning indicator does not reset, turn ignition switch Off and repeat procedure. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Change Reminder Lamp > Component Information > Service and Repair > Change Oil or Change Oil Now Message > Page 9237 Oil Change Reminder Lamp: Service and Repair Engine Oil Life Monitor ENGINE OIL LIFE MONITOR The "CHANGE OIL" monitor light on the instrument cluster is a reminder to change oil. When changing oil, reset the oil life monitor whether the "CHANGE OIL" light came on or not. NOTE: Disconnecting the negative battery cable will not reset the oil life monitor. Reset monitor as follows: 1. Turn ignition switch to "ON" position, but don't start engine. 2. Fully depress accelerator pedal to Wide Open Throttle (WOT) position and release it three times within five seconds. ^ The light is controlled by the Powertrain Control Module (PCM). The PCM is monitoring the TPS signal for 3 consecutive signals above 96%. The PCM will acknowledge, if the reset was successful, by flashing the "Change Oil" light twice, then turning off the light. 3. If "CHANGE OIL" warning/indicator lamp flashes then goes out, the system has been reset. 4. If "CHANGE OIL" warning/indicator lamp doesn't reset, turn ignition switch "OFF" and repeat procedure. ^ If "CHANGE OIL" light is inoperative or remains "ON," refer to Powertrain Management / Computerized Engine Controls / Testing Procedures section. (DTC 95) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Level Warning Indicator > Component Information > Description and Operation Oil Level Warning Indicator: Description and Operation DESCRIPTION This lamp illuminates to warn the driver that the engine oil level is low. When the ignition switch is first moved to Run, the oil level indicator lights for about 1 1/2 seconds as a bulb check. The oil level detection circuit has two internal timers. The first timer records the amount of time the ignition has been Off. The second timer records the amount of time the ignition has been On before the ignition was shut Off. The instrument cluster uses this information to determine if the engine has been sitting long enough for the oil to have returned to the oil pan. OPERATION The oil level monitoring circuits will check the oil level switch under the following conditions: 1. Ignition has been turned Off for more than 30 minutes. 2. Ignition has been Off for at least three minutes after ignition has been On for at least 12 minutes. If the oil level is low (oil level switch open), the "Check Oil" indicator will be turned On for the remainder of the ignition cycle. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator Inoperative W/Oil Level Low Fig. 99 Chart 8: Low Oil Level Indicator Inoperative W/Oil Level Low Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Level Warning Indicator > Component Information > Testing and Inspection > Low Oil Indicator Inoperative W/Oil Level Low > Page 9243 Oil Level Warning Indicator: Testing and Inspection Low Oil Indicator On w/Oil Level OK Fig. 98 Chart 7: Low Oil Level Indicator On W/Oil Level OK Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Pressure Gauge > Component Information > Description and Operation Oil Pressure Gauge: Description and Operation DESCRIPTION This oil pressure indicating system incorporates an instrument voltage regulator, electrical oil pressure gauge and a sending unit which are connected in series. The sending unit consists of a diaphragm, contact and a variable resistor. OPERATION As oil pressure increases or decreases, the diaphragm actuated the contact on the variable resistor, in turn controlling current flow through the gauge. When oil pressure is low, the resistance of the variable resistor is high, restricting current flow to the gauge, in turn indicating low oil pressure. As oil pressure increases, the resistance of the variable resistor is lowered, permitting an increased current flow to the gauge, resulting in an increased gauge reading. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Pressure Gauge > Component Information > Description and Operation > Page 9247 Oil Pressure Gauge: Service and Repair Disconnect the oil pressure gauge lead from the sending unit, connect a 12 volt test lamp between the gauge lead and the ground and turn ignition on. If test lamp flashes, the instrument voltage regulator is functioning properly and the gauge circuit is not broken. If the test lamp remains lit, the instrument voltage regulator is defective and must be replaced. If the test lamp does not light, check the instrument voltage regulator for proper ground or an open circuit. Also, check for an open in the instrument voltage regulator to oil pressure gauge wire or in the gauge itself. If test lamp flashes and gauge is not accurate, the gauge may be out of calibration, requiring replacement. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Pressure Sender > Component Information > Locations Rear Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Oil Level Sensor <--> [Oil Temperature Gauge] > Component Information > Testing and Inspection Oil Level Sensor: Testing and Inspection Check for a defective wire inside the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with the system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch > Page 9258 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Technical Service Bulletins > IP Dimmer Control - Proper Setting Dimmer Switch: Technical Service Bulletins IP Dimmer Control - Proper Setting File In Section: 08 - Body and Accessories Bulletin No.: 99-08-42-009 Date: November, 1999 INFORMATION Subject: Proper Setting of I/P Dimmer Control to View PRNDL Display with Automatic Headlamp Control Models: 2000 and Prior All Passenger Cars and Trucks With Automatic Headlamp Control and Electronic PRNDL Display Under certain conditions, if the instrument panel dimmer control is turned relatively low, the PRNDL will not be visible until the automatic headlamp control turns the headlamps off and the daytime running lamps (DRL) are turned back on. Such a condition may be if the vehicle is first started in an environment where the headlamp control turns on the headlamps and then the vehicle is driven out into a brighter environment (for example, when a vehicle is backed out of a dark garage into the bright sunlight). This condition is normal and any repair attempt will not be successful. Demonstrate this condition to the customer using the service lane and then turn the instrument panel dimmer control to a higher setting. This will enable the driver to see the PRNDL display Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Component Locations Dimmer Switch: Component Locations Lower LH Side Of Steering Column Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Component Locations > Page 9266 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Page 9267 Dimmer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Dimmer Switch > Component Information > Locations > Page 9268 Dimmer Switch: Service and Repair Fig. 13 Column Mounted Dimmer Switch Installation 1. Disconnect battery ground cable. 2. Remove instrument panel lower trim and on models with A/C, remove A/C duct extension at column. 3. Disconnect shift indicator from column and remove toe-plate cover screws. 4. Remove two nuts from instrument panel support bracket studs and lower steering column, resting steering wheel on front seat. 5. Remove dimmer switch retaining screws, then the switch. Tape actuator rod to column and separate switch from rod. 6. Reverse procedure to install. To adjust switch, depress dimmer switch slightly and install a 3/32 inch twist drill to lock switch to the body, Fig. 13. Force switch upward to remove lash between switch and pivot, then remove tape from actuator rod. Remove twist drill and check for proper operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9273 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9274 Door Switch: Locations Door Jamb Switch, RH Front Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9275 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9276 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Fuel Gauge Sender > Component Information > Locations Fuel Gauge Sender: Locations Mounted on Fuel Tank, Part of Fuel Tank Unit Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Fuel Gauge Sender > Component Information > Locations > Page 9280 Fuel Pump/Sender Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch LH Kick Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Sensors and Switches - Instrument Panel > Parking Brake Warning Switch > Component Information > Locations > Park Brake Indicator Switch > Page 9285 Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 9294 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 9295 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > Recalls for Shift Indicator: > 95C61 > Dec > 95 > Recall - A/T Shift Control Linkage Adjustment > Page 9296 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall A/T Shift Control Linkage Adjustment Technical Service Bulletin # 95C61 Date: 951201 Recall - A/T Shift Control Linkage Adjustment No. 95-C-61 Date: 12-01-95 SUBJECT: PRODUCT SAFETY CAMPAIGN 95-C-61 - STEERING COLUMN TRANSMISSION SHIFT CONTROL ADJUSTMENT Model and Year: 1995 CAPRICE/IMPALA To: ALL Chevrolet Dealers The National Traffic and Motor Vehicle Safety Act, as amended, provides that each vehicle subject to a recall campaign of this type must be adequately repaired within a reasonable time after the owner has tendered it for repair. A failure to repair within sixty (60) days after tender of a vehicle is prima facie evidence of failure to repair within a reasonable time. If the condition is not adequately repaired within a reasonable time, the owner may be entitled to an identical or reasonable equivalent vehicle at no charge or to a refund of the purchase price less a reasonable allowance for depreciation. To avoid having to provide these burdensome solution, every effort must be made to promptly schedule an appointment with each owner and to repair their vehicle as soon as possible. As you will see in reading the included copy of the letter that is being sent to owners, the owners are being instructed to contact the Chevrolet Customer Assistance Center if their dealer does not remedy the condition within five (5) days of the mutually agreed upon service date. If the condition is not remedied within a reasonable time, they are instructed on how to contact The National Highway Traffic Safety Administration. Defect & Vehicles Involved DEFECT INVOLVED General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, "Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the 'park' position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, dealers are to perform an adjustment to the shift control linkage system. VEHICLES INVOLVED Involved are certain 1995 Chevrolet Caprice/Impala models vehicles built within the VIN breakpoints as shown. Involved vehicles have been identified by Vehicle Identification Number Computer Listings. Computer listings contain the complete Vehicle Identification Number, owner name and address data, and are furnished to involved dealers with the campaign bulletin. Owner name and address data furnished will enable dealers to follow-up with owners involved in this campaign These listings may contain owner names and addresses obtained from State Motor Vehicle Registration Records. The use of such motor vehicle registration data for any other purpose is a violation of law in several states. Accordingly, you are urged to limit the use of this listing to the Follow-up necessary to complete this campaign. Any dealer not receiving a computer listing with the campaign bulletin has no involved vehicles currently assigned. Parts Information No parts are required. Owner Notification & Dealer Campaign Responsibility OWNER NOTIFICATION Owners will be notified of this campaign on their vehicles by Chevrolet Motor Division (see copy of owner letter included with this bulletin). DEALER CAMPAIGN RESPONSIBILITY Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall A/T Shift Control Linkage Adjustment > Page 9302 All unsold new vehicles in dealers, possession and subject to this campaign must be held and inspected/repaired per the service procedure of this campaign bulletin before owners take possession of these vehicles. Dealers are to service all vehicles subject to this campaign at no charge to owners, regardless of mileage, age of vehicle, or ownership, from this time forward. Owners of vehicles recently sold from your new vehicle inventory with no owner information indicated on the dealer listing, are to be contacted by the dealer, and arrangements made to make the required correction according to the instructions contained in this bulletin. This could be done by mailing to such owners a copy of the letter accompanying this bulletin. Campaign follow-up cards should not be used for this purpose, since the owner may not as yet have received the notification letter. In summary, whenever a vehicle subject to this campaign enters your vehicle inventory or is in your dealership for service in the future, please take the steps necessary to be sure the campaign correction has been made before selling or releasing the vehicle. Service Procedure NOTE: The shift linkage must be adjusted each time the transmission is replaced. 1. Place vehicle on hoists. Place steering column range selector in the "N" (neutral) position. IMPORTANT: The vehicle must be at the correct trim height for proper linkage adjustment. The vehicle must be supported by all four (4) tires or by jack stands on the rear axle tube such that the suspension is at the proper trim height. 2. Loosen screw, automatic transmission range selector rod swivel (Figure 1, Item 816). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall A/T Shift Control Linkage Adjustment > Page 9303 3. Hang a weight (approximately three (3) pounds 1.4 Kilograms) on the end of the steering column selector lever to bias the selector lever toward but not into the "OD" (overdrive) position. See Figure 2. 4. Verify that transmission is in "Neutral" position. 5. Tighten screw, automatic transmission range selector rod swivel, (Figure 1, Item 816) to 28 Nm (21 lb. ft.). 6. Inspect to ensure the steering column selector lever has not moved from the "N" (neutral) position. 7. Verify the transmission shift control system is properly adjusted. a. With ignition key removed, while attempting to shift the steering column selector lever from "P" (park) into the "R" (reverse) position, verify the vehicle will not roll either by placing the vehicle on an incline or by pushing the vehicle. NOTE: If the transmission shift control system is improperly adjusted, the column select lever may not have been completely out of the "P" (park) position in order for the vehicle to roll. b. Verify the proper operation of steering column selector lever and transmission in all gear ranges. If transmission is not functioning properly, repeat steps 1 through 7. 8. Install Campaign Identification Label. Campaign ID Label and Claim Information CAMPAIGN IDENTIFICATION LABEL Each vehicle corrected in accordance with the instructions outlined in this Product Campaign Bulletin will require a "Campaign Identification Label". Each label provides a space to include the campaign number and the five (5) digit dealer code of the dealer performing the campaign service. This information may be inserted with a typewriter or a ball point pen. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Shift Indicator: > 95C61 > Dec > 95 > Recall A/T Shift Control Linkage Adjustment > Page 9304 Each "Campaign Identification Label" is to be located on the radiator core support in an area which will be visible when the vehicle is brought in for periodic servicing by the owner. When installing the new Campaign Identification Label, be sure to install the clear protective covering. Additional Campaign Identification Labels can be obtained from VISPAC Incorporated by calling 1-800-269-5100 (Monday-Friday, 8:00 a.m. to 4:30 p.m. EST). Ask for Item Number S-1015 when ordering. Apply "Campaign Identification Label", only on a clean dry surface. CLAIM INFORMATION Submit a Product Campaign Claim with the information indicated as shown. Refer to the General Motors Claims Processing Manual for details on Product Campaign Claim Submission. Owner Letter Dear Chevrolet Customer: This notice is sent to you in accordance with the requirements of the National Traffic and Motor Vehicle Safety Act. REASON FOR THIS RECALL General Motors has decided that certain 1995 Chevrolet Caprice/Impala model vehicles fail to conform to Federal Motor Vehicle Safety Standard (FMVSS) 114, 'Theft protection". Some of these vehicles have been produced with an improperly adjusted shift control linkage. As a result, it may be possible to shift from the "park" position with the ignition key removed. This condition may increase the risk of accidents resulting from unauthorized use or from the unintended movement of parked vehicles. WHAT WE WILL DO To prevent the possibility of this condition occurring, and in order to comply with FMVSS 114, your dealer will adjust the shift control linkage system. This service will be performed for you at no charge. WHAT YOU SHOULD DO Please contact your Chevrolet dealer as soon as possible to arrange a service date for the repair. Instruction for making this correction have been sent to your dealer. The labor time necessary to perform this service correction is approximately 25 minutes. Please ask your dealer if you wish to know how much additional time will be needed to schedule and process your vehicle. The enclosed owner reply card identifies your vehicle. Presentation of this card to your dealer will assist in making the necessary correction in the shortest possible time. If you have sold or traded your vehicle, please let us know by completing the postage paid reply card and returning it to us. Your Chevrolet dealer is best equipped to provide service to ensure that your vehicle is corrected as promptly as possible. If, however, you take your vehicle to your dealer on the agreed service date, and they do not remedy this condition on that date or within five (5) days, we recommend you contact the Chevrolet Customer Assistance Center by calling 1-800-222-1020. After contacting your dealer and the Customer Assistance Center, if you are still not satisfied that we have done our best to remedy this condition without charge and within a reasonable time, you may wish to write the administrator, National Highway Traffic Safety Administration, 400 Seventh Street, S.W., Washington, D.C. 20590 or call 1-800-424-9393 (Washington D.C. residents use 202-366-0123). We are sorry to cause you this inconvenience; however, we have taken this action in the interest of your continued satisfaction with our products. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > Page 9305 Shift Indicator: Description and Operation DESCRIPTION This lamp is used on most models equipped with manual transmission. OPERATION The Upshift lamp is illuminated to inform the driver of ideal shift points, with improved fuel economy as the specific objective. When the light is illuminated, the transmission should be shifted to the next highest gear, if driving conditions permit such an action. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Shift Indicator > Component Information > Technical Service Bulletins > Page 9306 Shift Indicator: Service and Repair If upshift indicator is not working properly, perform the following test. 1. Disconnect ECM connector C1. 2. Place ignition switch in run. 3. Measure voltage at terminal A2 of ECM connector. 4. If battery voltage is present, further ECM diagnosis is necessary. 5. If battery voltage is not present, repair open circuit in brown/black wire, circuit 456. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Speedometer Head > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations Speedometer Head: Technical Service Bulletins Odometer/Speedometer - ACDelco Service Center Locations File In Section: 8 - Chassis/Body Electrical Bulletin No.: 66-83-04A Date: September, 1996 INFORMATION Subject: AC Delco Service Center Locations for Odometer/Speedometer Service Models: 1997 and Prior Passenger Cars and Trucks (excluding Cadillac) This bulletin is being revised to provide the necessary contact information only. Please discard Corporate Bulletin Number 66-83-04 (Section 8 - Chassis/Body Electrical) General Motors provides service for sophisticated electronic products through the authorized AC Delco Service Center Program. This program is designed to provide GM vehicle owners with the highest quality and most technically up-to-date product available. Repair products from unauthorized service outlets are not acceptable as warranty replacements. Currently, there are 25 authorized AC Delco Service Centers who exchange and remanufacture odometer/speedometers (list included). Only these Centers should be contacted for service. Important: W series and 1997 T series Medium Duty truck odometer/speedometers must be ordered directly from GMSPO. The following steps should be taken when utilizing the AC Delco Service Centers: Dealers should contact their local AC Delco Service Center (list included). Any listed facility may be used. The following information must be provided: Part number VIN, Mileage, Vehicle Year, Make and Model Dealer Name and Address Delivery Date of Vehicle Name of the person requesting exchange or service Phone number Repair Order Number P.O. number (if non - warranty) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Speedometer Head > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations > Page 9311 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Speedometer Head > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations > Page 9312 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Speedometer Head > Component Information > Technical Service Bulletins > Odometer/Speedometer - ACDelco Service Center Locations > Page 9313 AC Delco Service Centers Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Speedometer Head > Component Information > Technical Service Bulletins > Page 9314 Speedometer Head: Description and Operation DESCRIPTION The Vehicle Speed Sensor (VSS) generates a signal that indicates the vehicle speed. The signal is processed by the powertrain control module (PCM) to supply inputs to the speedometer and odometer. OPERATION The VSS is mounted in the transaxle and generates an AC voltage signal with a frequency proportional to vehicle speed. The PCM takes the voltage pulses from the sensor and uses them to close a solid state output switch. The output terminal is switched to ground at a rate proportional to vehicle speed. The speedometer and odometer are switched at the same frequency that the sensor generates at. The speedometer and odometer are operated by a circuit board in the instrument cluster that converts pulses received from the PCM into a control signal for the vacuum fluorescent display. Check for a broken, or partially broken, wire inside the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Speedometer Head > Component Information > Technical Service Bulletins > Page 9315 Speedometer Head: Testing and Inspection Fig. 102 Chart 11: Speedometer & Cruise Control Inoperative Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Temperature Gauge > Component Information > Description and Operation Temperature Gauge: Description and Operation DESCRIPTION This temperature indicating system consists of a sending unit, located on the cylinder head, electrical temperature gauge and an instrument voltage regulator. OPERATION As engine temperature increases or decreases, the resistance of the sending unit changes, in turn controlling current flow through the gauge. When engine temperature is low sending unit resistance is high, current flow through the gauge is restricted, and the gauge pointer remains against the stop or moves very little. As engine temperature increases sending unit resistance decreases and current flow through the gauge increases, resulting in increased pointer movement. Troubleshooting for the electrical temperature indicating system is the same as for the electrical oil pressure indicating system. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Temperature Gauge > Component Information > Description and Operation > Page 9319 Temperature Gauge: Testing and Inspection Fig. 104 Chart 2: Engine Coolant Temperature Gauge Inoperative Or Inaccurate Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Temperature Sensor (Gauge) > Component Information > Locations Temperature Sensor (Gauge): Locations ENGINE COOLANT TEMPERATURE GAUGE SENSOR Lower Right Side Of Engine The Engine Coolant Temperature Gauge Sensor is located forward LH side of Engine Block, below manifold. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Temperature Warning Lamp/Indicator, Engine Cooling > Component Information > Description and Operation Temperature Warning Lamp/Indicator: Description and Operation DESCRIPTION If the red light is not lit when the engine is being cranked, check for a burned out bulb, an open in the light circuit, or a defective ignition switch. If the red light is lit when the engine is running, check the wiring between light and switch for a ground, temperature switch defective, or overheated cooling system. As a test circuit to check whether the red bulb is functioning properly, a wire which is connected to the ground terminal of the ignition switch is tapped into its circuit. When the ignition is in the start engine cranking position, the ground terminal is grounded inside the switch and the red bulb will be lit. When the engine is started and the ignition switch is in the on position, the test circuit is opened and the bulb is then controlled by the temperature switch. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Transmission Shift Position Indicator Lamp > Component Information > Technical Service Bulletins > Instruments - Reduced PRNDL Display Visibility Transmission Shift Position Indicator Lamp: Technical Service Bulletins Instruments - Reduced PRNDL Display Visibility Bulletin No.: 02-08-42-004A Date: March 30, 2007 INFORMATION Subject: PRNDL Display Reduced Visibility For Approximately One Minute Models: 2007 and Prior Passenger Cars and Trucks (Including Saturn) 2007 and Prior HUMMER H2, H3 2005-2007 Saab 9-7X with Automatic Headlamp Control and Vacuum Fluorescent PRNDL Indicator Instrument Panel Cluster Supercede: This bulletin is being revised to include additional models and model years. Please discard Corporate Bulletin Number 02-08-42-0004 (Section 08 - Body and Accessories). After backing the vehicle out of a garage or dark environment into a daylight environment, the PRNDL display has reduced visibility for approximately one minute. While the vehicle is parked in a dark environment, the sensor for the automatic headlamp/driving lamps senses that it is dark. When the key is turned to the run/start position, the automatic headlamp module will turn all driving lamps, the instrument panel cluster and PRNDL display ON in the night-time mode. The night-time mode intensity of the instrument panel lamps and PRNDL display is controlled by the automatic headlamp module and can be dimmed further by the customer using the dimming control of the headlamp switch. When the customer then moves the vehicle from the dark environment into the bright sunlight, it will take approximately one minute before the headlamp control module recognizes this as true daylight and not just a bright overhead street lamp shining on the sensor. The headlamp control module will then turn the headlamps off and restore the instrument panel and PRNDL display to full brilliance. Without the time delay, the automatic headlamp control module would switch to the night mode (turn on all driving lamps, instrument panel lamps and PRNDL display would dim) each time the vehicle was driven under an overpass or other darkened environment. This is a normal condition and no repair should be attempted. Ensure the instrument panel backlighting control is in the full bright position. This will help alleviate the condition. You may demonstrate to the customer what happens by placing a repair order over the automatic headlamp control light sensor, which will cause the automatic headlamp control module to switch to the night mode in approximately one minute. All driving lamps will come ON, the instrument panel backlight will be dim, and the PRNDL display will also dim to the night setting in conjunction with the position of the headlamp switch dimming control. Demonstrate to the customer the variance in the instrument panel backlighting and PRNDL display while adjusting the headlamp switch dimming control to both ends of its allowable range. Advise the customer to keep the headlight switch dimming control in the highest position to allow viewing of the PRNDL display in a bright environment. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Description and Operation Volt Meter Gauge: Description and Operation DESCRIPTION The voltmeter is a gauge which measures the electrical flow from the battery to indicate whether the battery output is within tolerances. The voltmeter reading can range from 13.5-14.0 volts under normal operating conditions. If an undercharge or overcharge condition is indicated for an extended period, the battery and charging system should be checked. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Volt Meter Gauge: Initial Inspection and Diagnostic Overview Circuit Operation - Starter Battery voltage is applied to the Ignition Switch at all times through Maxifuse 11. When the Ignition Switch is turned to "START" battery voltage is applied through the closed contacts of the Ignition Switch, (through the contacts of the Theft Deterrent Relay. This relay is controlled by the Theft Deterrent Module, (NON SEO)). Then it goes to the Starter Solenoid at terminal "S". When battery voltage is applied to terminal "S" of the Starter Solenoid Switch, the Hold-In Coil and Pull-In Coil of the Starter Solenoid switch are energized with the Pull-In Coil grounded through the Starter Motor. The coils, when energized, work together to pull in and hold the Plunger of the Starter Solenoid switch. As the Plunger is pulled in, it closes the Starter Solenoid Switch contacts and causes the Shift Lever to rotate, engaging the Drive Assembly to the Flywheel. With battery voltage applied directly to the Starter Motor through the closed Solenoid Contacts, the Starter Motor begins to rotate the Drive Assembly as the Drive Assembly comes in contact with the Flywheel. The Pull-In Coil is de-energized by having battery voltage at both ends of the coil. The Starter Motor continues to rotate to crank the Engine through the Drive Assembly-Flywheel gear combination. Battery voltage is removed from the Starter Solenoid terminal "S" when the Ignition Switch is released from the "START" position. The Hold-In Coil is de-energized and the return spring in the Starter Solenoid Switch causes the Plunger to disengage the Drive Assembly from the Flywheel. As the Plunger returns, the Plunger opens the Solenoid Contacts removing battery voltage from the Starter Motor. Circuit Operation - Charging The Generator provides voltage to operate the vehicle's electrical system and charge the Battery. The Regulator supplies current to the field coil of the Rotor. When current flows through the field coil, a magnetic field is created. This field rotates as the Rotor is driven by the Engine, creating an AC voltage and current in the Stator windings. This AC signal is converted to DC by the rectifier bridge and available to the vehicle's electrical system at the "BAT" terminal. The Generator must supply sufficient current to all vehicle electrical loads especially for charging the vehicle's Battery. Since the Rotor speed varies with Engine speed, the Generator must also maintain the output voltage at a constant value. The Generator's Regulator switches current to the field coil of the Rotor on or off controlling the output voltage of the Generator. When the Ignition Switch is turned to "RUN," battery voltage is supplied from U/Hood Fuse #8 to the Generator at terminal "F", turning on the Regulator. If for any reason terminal "F" did not supply any current to the connection inside the Generator, the Regulator could still turn on because CKT 25 would function as a backup source of "TURN ON" current. The Regulator switches on the field current by connecting the field coil of the Rotor to battery voltage available at the "BAT" terminal. The field current creates a weak magnetic field in the field coil when the Engine is being started. The Regulator senses Generator rotation by detecting an AC voltage at the Stator through an internal wire. Once the Engine is running, the Regulator can monitor the internal AC voltage and DC output at the " BAT" terminal. The Regulator will then vary the current in the field coil of the Rotor as needed, to provide a constant output voltage and adequate current to the electrical system of the vehicle. Circuit Operation - Check Gage Indicator Battery voltage is applied to the Instrument Cluster through I/P Fuse #11 whenever the Ignition Switch is in "RUN," or "START." A ground is provided at the Generator "L" terminal when the Regulator senses a high or low voltage condition or when the Rotor stops turning. Troubleshooting Hints - Charging System PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: 1. Visually inspect the hydrometer (built into Battery). ^ Green dot - Battery is charged. ^ Dark dot - Charge and load test Battery. If Battery passes load test, refer to System Diagnosis. See: Starting and Charging/Testing and Inspection/Initial Inspection and Diagnostic Overview/Preliminary Information - Starting System ^ Clear or light yellow dot - Battery electrolyte is low. Replace Battery. 2. Check U/Hood Fuse #8 and I/P Fuse #11. Check Maxifuse 11. 3. Check that the Generator Connector and Generator "BAT" terminal are both clean and tight. 4. Check that the Battery connections are clean and tight. 5. Check Generator belt. ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system failure but prove "GOOD" in a continuity/voltage check (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). ^ Refer to System Diagnosis. Troubleshooting Hints - Starter PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: 1. Visually inspect the hydrometer (built into Battery). ^ Green dot - Battery is charged. ^ Dark dot - Charge and load test Battery.If Battery passes load test, refer to System Diagnosis. See: Starting and Charging/Testing and Inspection/Initial Inspection and Diagnostic Overview/Preliminary Information - Starting System Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9335 ^ Clear or light yellow dot - Battery electrolyte is low. Replace Battery. 2. Check that Starter Solenoid Switch terminals "S" and B" and Battery connections are clean and tight. 3. Check that Maxifuse #11 and I/P Fuse #24 are OK. If these fuses are open, check for a short to ground in CKT 5, CKT 142 or CKT 806. 4. Check that G100 and G101 are clean and tight. ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove "GOOD" in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational (under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids ^ Refer to System Diagnosis. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9336 Volt Meter Gauge: Symptom Related Diagnostic Procedures Symptom Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9337 Chart #1 Engine Does Not Crank, Starter Solenoid Switch Does Not Click Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9338 Chart #2 Starter Solenoid Switch Click, Engine Does Not Crank Chart #3 Battery Is Undercharged Or Overcharged Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9339 Chart #4 VOLTS Or CHECK GAGE Indicator ON At All Times Chart #5 VOLTS Or CHECK GAGE Indicator Inoperative Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Instrument Panel, Gauges and Warning Indicators > Volt Meter Gauge > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9340 Volt Meter Gauge: Component Tests and General Diagnostics To test meter, turn key and headlights On with engine Off. Pointer should move to 12.5 volts. If no needle movement is observed, check connections from battery to circuit breaker. If connections are tight and meter shows no movement, check wire continuity. If wire continuity is satisfactory, the meter is inoperative and must be replaced. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Ambient Light Sensor > Component Information > Locations Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Backup Lamp > Backup Lamp Switch > Component Information > Locations Backup Lamp Switch: Locations RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Backup Lamp > Backup Lamp Switch > Component Information > Locations > Page 9349 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement Brake Lamp: Technical Service Bulletins Lighting - Exterior Lamp Condensation and Replacement INFORMATION Bulletin No.: 01-08-42-001H Date: January 05, 2011 Subject: Exterior Lamp Condensation and Replacement Guidelines Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) Supercede: This bulletin is being revised to add the 2011 model year. Please discard Corporate Bulletin Number 01-08-42-001G (Section 08 - Body and Accessories). The following information is being provided to better define the causes of condensation in exterior lamps and includes guidelines for determining the difference between a lamp with a normal atmospheric condition (condensation) and a lamp with a water leak. Some exterior lamps, such as cornering, turn signal, backup, headlamps or tail lamps may exhibit very small droplets of water, a fine mist or white fog (condensation) on the inside of the lamp lens. This may be more noticeable on lamps with "multi-lens" designs and may be normal during certain weather conditions. Condensation occurs when the air inside the lamp assembly, through atmospheric changes, reaches the "dew point". When this takes place, the moisture in the air within the lamp assembly condenses, creating a fine mist or white fog on the inside surface of the lamp lens. Most exterior lamps on General Motors vehicles use a vented design and feature a replaceable bulb assembly. They are designed to remove any accumulated moisture vapor by expelling it through a vent system. The vent system operates at all times, however, it is most effective when the lamps are ON or when the vehicle is in motion. Depending on the size, shape and location of the lamp on the vehicle, and the atmospheric conditions occurring, the amount of time required to clear the lamp may vary from 2 to 6 hours. Completely sealed headlamp assemblies (sealed beams) are still used on a limited number of models being manufactured today. These lamps require the replacement of the complete lamp assembly if a bulb filament burns out. Condensation 2006 TrailBlazer Shown A Fine Mist or White Fog on the Inside Surface of the Lamp Lens Occurring After a Period of High Humidity - May be located primarily in the lens corners (near the vents) and SHOULD NOT cover more than half the lens surface. - The condition should clear of moisture when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a SIMILAR performance. If the above conditions are noted, the customer should be advised that replacement of a lamp assembly may not correct this condition. Water Leak New Style Pickup Shown Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement > Page 9354 Numerous & Various Size Drops of Water Collecting on the Inside Surface of the Lamp Lens After the Vehicle Has Been Exposed to Rain or a Car Washing Environment - A condition that covers more than half the surface of the lamp lens. - An accumulation of water in the bottom of the lamp assembly. - A condition that WON'T clear when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a different performance. Any of the above conditions would indicate the need to service the lens or lamp assembly. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Lamp > Component Information > Locations > Inboard Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Lamp > Component Information > Locations > Inboard > Page 9357 LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Lamp > Component Information > Locations > Inboard > Page 9358 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Lamp > Component Information > Locations > Inboard > Page 9359 LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Lamp > Component Information > Locations > Page 9360 Brake Lamp: Description and Operation Voltage is applied at all times from I/P Fuse #37 to the Stoplamp Switch. When the brake pedal is depressed, voltage is applied from the Stoplamp Switch and Turn Signal Switch to CKT 18 and CKT 19, turning "ON" the LH and RH Tail/Stop/Turn Lamps. Voltage is supplied at all times through I/P Fuse #37 to the Stoplamp/Cruise Release Switch. When the brake pedal is depressed, voltage is applied from the Stoplamp/Cruise Release Switch to CKT 17 and the High Mount Stoplamp, turning "ON" the High Mount Stoplamp. Buick Wagons with Remote Keyless Entry (AUO) have a 400 ohm resistor in CKT 17 and CKT 750. This Resistor is used to prevent accidental locking of the door locks in cases where the Hazard Switch has been activated and the rear glass is released. Residual voltage in CKT 17 could cause the Remote Control Door Lock Receiver to activate a Door Lock Cycle. The 400 ohm resistor will keep CKT 17 "LOW," thus preventing an unwanted Lock Cycle. Refer to Keyless Entry for additional information on the Remote Keyless Entry System. See: Accessories and Optional Equipment/Antitheft and Alarm Systems/Remote Keyless Entry Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Light Switch > Component Information > Locations Brake Light Switch: Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Light Switch > Component Information > Locations > Page 9364 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Brake Light Switch > Component Information > Locations > Page 9365 Brake Light Switch: Service and Repair The stop light switch has a slip fit in the mounting sleeve which permits positive adjustment by pulling the brake pedal up firmly against the stop. The pedal arm forces the switch body to slip in the mounting sleeve bushing to position the switch properly. 1. Disconnect wires from switch and remove switch from bracket. 2. Position replacement switch in bracket and push inward until fully seated. Brake pedal arm moves switch to correct distance on rebound. Check if pedal is in full return position by lifting slightly by hand. 3. Connect switch electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions Center Mounted Brake Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9370 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9371 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9372 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9373 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9374 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9375 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9376 Center Mounted Brake Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9377 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9378 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9379 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9380 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9381 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9382 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9383 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9384 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9385 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9386 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9387 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9388 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9389 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9390 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9391 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9392 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9393 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9394 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9395 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9396 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9397 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9398 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9399 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9400 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9401 Center Mounted Brake Lamp: Electrical Diagrams Turn/Stop/Hazard/High Mount Stop Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Center Mounted Brake Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9402 Turn/Stop/Hazard/High Mounted Stop/Front Marker/Park/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Coach Lamp > Component Information > Locations > Opera Lamp Coach Lamp: Locations Opera Lamp LH Outside LH "C" Pillar RH Outside RH "C" Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Coach Lamp > Component Information > Locations > Opera Lamp > Page 9407 Coach Lamp: Locations Spot Lamp (Seo) LH At LH "A" Pillar RH At RH "A" Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Locations > Component Locations Cornering Lamp: Component Locations LH Forward Lamp Wiring RH Forward Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Locations > Component Locations > Page 9412 Cornering Lamp: Connector Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Locations > Component Locations > Page 9413 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions Cornering Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9416 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9417 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9418 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9419 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9420 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9421 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9422 Cornering Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9423 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9424 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9425 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9426 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9427 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9428 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9429 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9430 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9431 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9432 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9433 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9434 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9435 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9436 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9437 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9438 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9439 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9440 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9441 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9442 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9443 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9444 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9445 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9446 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9447 Cornering Lights Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Diagrams > Page 9448 Cornering Lamp: Description and Operation Voltage is applied to the Headlamp Switch at all times. With the Headlamp Switch in "PARK" or "HEAD," voltage is applied to the Cornering Lamps Switch, which is part of the Turn/Signal Switch Assembly. With the Turn Signal Switch in either the "TURN LEFT" or "TURN RIGHT" position, voltage is supplied to the corresponding Front Sidemarker and Cornering Lamp. Both Lamps are permanently grounded, the LH Lamp to G102 and the RH Lamp to G106. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview Cornering Lamp: Initial Inspection and Diagnostic Overview Circuit Operation Voltage is applied to the Headlamp Switch at all times. With the Headlamp Switch in "PARK" or "HEAD," voltage is applied to the Cornering Lamps Switch, which is part of the Turn/Signal Switch Assembly. With the Turn Signal Switch in either the "TURN LEFT" or "TURN RIGHT" position, voltage is supplied to the corresponding Front Sidemarker and Cornering Lamp. Both Lamps are permanently grounded, the LH Lamp to G102 and the RH Lamp to G106. Troubleshooting Hints PERFORM BEFORE BEGINNING SYSTEM DIAGNOSIS: 1. Check I/P Fuse #31. If it is open, check CKT 240 for a short to ground. 2. Check I/P Fuse #41. If it is open, check CKT 308 for a short to ground and Refer to Exterior Lights for Diagnosis of Park Lamps. See: Testing and Inspection 3. Make sure that G102 and G106 are clean and tight. 4. Check bulbs and sockets for damage or corrosion. ^ Check for a broken (or partially broken) wire inside of the insulation which could cause system malfunction but prove G00D in a continuity/voltage check with a system disconnected. These circuits may be intermittent or resistive when loaded, and if possible, should be checked by monitoring for a voltage drop with the system operational under load). ^ Check for proper installation of aftermarket electronic equipment which may affect the integrity of other systems (refer to "General Troubleshooting Procedures,"). See: Diagrams/Diagnostic Aids ^ Refer to System Diagnosis. See: Component Tests and General Diagnostics/System Diagnosis Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9451 Cornering Lamp: Component Tests and General Diagnostics Chart #1 Both Cornering Lamps Are Inoperative, Park Lamps Operate Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9452 Chart #2 One Cornering Lamp Is Inoperative Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Cornering Lamp > Component Information > Testing and Inspection > Initial Inspection and Diagnostic Overview > Page 9453 Chart #3 One Cornering Lamp Is ON Whenever Park Lamps Are Activated Symptom Table System Diagnosis ^ Refer the Symptom Table for the appropriate diagnostic procedure(s). See: Symptom Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Courtesy Lamp > Ash Tray Lamp > Component Information > Locations Front Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Courtesy Lamp > Courtesy Lamp Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Courtesy Lamp > Door Lamp > Component Information > Locations > Courtesy Lamp, Front Door Door Lamp: Locations Courtesy Lamp, Front Door LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Courtesy Lamp > Door Lamp > Component Information > Locations > Courtesy Lamp, Front Door > Page 9465 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Courtesy Lamp > Door Lamp > Component Information > Locations > Courtesy Lamp, Front Door > Page 9466 Door Lamp: Locations Door Handle Lamp LH LH Front Door RH RH Front Door Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Courtesy Lamp > Door Lamp > Component Information > Locations > Courtesy Lamp, Front Door > Page 9467 Door Lamp: Locations Door Lock Switch Lamp LH LH Front door RH RH Front Door Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Courtesy Lamp > Glove Box Lamp > Component Information > Locations Back View Of RH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Daytime Running Lamp > Daytime Running Lamp Control Unit > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Daytime Running Lamp > Daytime Running Lamp Control Unit > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 9476 RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Daytime Running Lamp > Daytime Running Lamp Control Unit > Component Information > Locations > Page 9477 Daytime Running Lamp Control Unit: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Daytime Running Lamp > Daytime Running Lamp Diode Assembly > Component Information > Locations Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Daytime Running Lamp > Daytime Running Lamp Relay > Component Information > Diagrams Theft Deterrent Relay Daytime Running Lamps (DRL) Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Dimmer Switch > Component Information > Technical Service Bulletins > IP Dimmer Control - Proper Setting Dimmer Switch: Technical Service Bulletins IP Dimmer Control - Proper Setting File In Section: 08 - Body and Accessories Bulletin No.: 99-08-42-009 Date: November, 1999 INFORMATION Subject: Proper Setting of I/P Dimmer Control to View PRNDL Display with Automatic Headlamp Control Models: 2000 and Prior All Passenger Cars and Trucks With Automatic Headlamp Control and Electronic PRNDL Display Under certain conditions, if the instrument panel dimmer control is turned relatively low, the PRNDL will not be visible until the automatic headlamp control turns the headlamps off and the daytime running lamps (DRL) are turned back on. Such a condition may be if the vehicle is first started in an environment where the headlamp control turns on the headlamps and then the vehicle is driven out into a brighter environment (for example, when a vehicle is backed out of a dark garage into the bright sunlight). This condition is normal and any repair attempt will not be successful. Demonstrate this condition to the customer using the service lane and then turn the instrument panel dimmer control to a higher setting. This will enable the driver to see the PRNDL display Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Dimmer Switch > Component Information > Locations > Component Locations Dimmer Switch: Component Locations Lower LH Side Of Steering Column Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Dimmer Switch > Component Information > Locations > Component Locations > Page 9490 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Dimmer Switch > Component Information > Locations > Page 9491 Dimmer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Dimmer Switch > Component Information > Locations > Page 9492 Dimmer Switch: Service and Repair Fig. 13 Column Mounted Dimmer Switch Installation 1. Disconnect battery ground cable. 2. Remove instrument panel lower trim and on models with A/C, remove A/C duct extension at column. 3. Disconnect shift indicator from column and remove toe-plate cover screws. 4. Remove two nuts from instrument panel support bracket studs and lower steering column, resting steering wheel on front seat. 5. Remove dimmer switch retaining screws, then the switch. Tape actuator rod to column and separate switch from rod. 6. Reverse procedure to install. To adjust switch, depress dimmer switch slightly and install a 3/32 inch twist drill to lock switch to the body, Fig. 13. Force switch upward to remove lash between switch and pivot, then remove tape from actuator rod. Remove twist drill and check for proper operation. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Dome Lamp > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9500 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9501 Door Switch: Locations Door Jamb Switch, RH Front Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9502 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9503 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Hazard Warning Lamps > Hazard Warning Flasher > Component Information > Locations Hazard Warning Flasher: Locations Mounted On HVAC Module Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 9513 RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 9514 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Control Module > Component Information > Locations > Page 9515 Headlamp Control Module: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Control Module > Component Information > Locations > Page 9516 Headlamp Control Module (C2) C406: Body Harness To Tailgate Harness, Headlamp Automatic Control Module (C1), Remote Control Door Lock Receiver Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Dimmer Switch > Component Information > Locations Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Lens > Component Information > Technical Service Bulletins > Lighting - Headlamp Polycarbonate Lens Damage Prevention Headlamp Lens: Technical Service Bulletins Lighting - Headlamp Polycarbonate Lens Damage Prevention INFORMATION Bulletin No.: 02-08-42-001D Date: June 21, 2010 Subject: Headlamp Lens Overheating When Covered and Chemical Damage to Exterior Polycarbonate Headlamp Lenses Models: 2011 and Prior GM Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add model years and to revise the warning statements. Please discard Corporate Bulletin Number 02-08-42-001C (Section 08 - Body and Accessories). The bulletin is being issued to make dealers and customers aware of chemical damage that may be caused to exterior polycarbonate headlamp lenses. Most late model vehicles have these types of headlamp lenses. This material is used because of its temperature and high impact resistance. A variety of chemicals can cause crazing or cracking of the headlamp lens. Headlamp lenses are very sensitive. Care should be exercised to avoid contact with all exterior headlamp lenses when treating a vehicle with any type of chemical, such as those recommended for rail dust removal. Rubbing compound, grease tar and oil removers, tire cleaners, cleaner waxes and even car wash soaps in too high a concentration may also attribute to this condition. This could result in the need to replace the entire headlamp housing. Warning Use only lukewarm or cold water, a soft cloth and a car washing soap to clean exterior lamps and lenses. Also, crazing or deformations of the lens may occur if a shop mat or fender cover is draped over the fender and covers a portion or all of the headlamp assembly while the DRL or headlamps are on. This action restricts the amount of heat dissipated by the headlamps. Warning Care should be taken to not cover headlamps with shop mats or fender covers if the vehicle is being serviced with the headlamps or DRL illuminated. Covering an illuminated lamp can cause excessive heat build up and crazing/deformation of the lens may occur. The degradation of the lens can be unnoticeable at first and eventually become hairline cracks in the lens. In extreme cases, it could cause the lens to deform. This damage can also be caused by aftermarket shields that are often tinted in color. Once a heat buildup is generated by the headlamp, a degradation of the headlamp lens begins. This degradation of the lens can be unnoticeable at first and eventually manifest as spider cracks. In more extreme cases, it will begin to melt the lens of the headlamp. Notice Headlamps damaged by chemicals, improper cleaning, or overheating due to being covered are not covered under the new vehicle warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector Twilight Sentinel Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 9528 Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 9529 Headlamp Switch: Locations Twilight Sentinel/Daytime Running Lamps Harness Back View Of RH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 9530 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Switch > Component Information > Locations > Page 9531 Headlamp Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Headlamp > Headlamp Switch > Component Information > Locations > Page 9532 Headlamp Switch: Service and Repair Fig. 7 Headlamp Switch Replacement 1. Disconnect battery ground cable. 2. Remove lower steering column trim panel attaching screws, then pull downward to remove. 3. Through glove compartment, unsnap righthand molding. 4. Loosen steering column support bracket to instrument panel carrier attaching bolts. Do not remove bolts. 5. Gently lower steering column assembly. Use extreme care when lowering steering to prevent damage to column assembly. 6. Remove lefthand trim plate to instrument panel carrier assembly six attaching screws, then unsnap lefthand trim assembly. 7. Remove headlamp switch attaching screws. 8. Pull switch rearward, then disconnect switch electrical connectors and remove, Fig. 7. 9. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Horn > Horn Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Horn > Horn Switch > Component Information > Locations Steering Wheel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Locations Trunk Lid Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions License Plate Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9545 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9546 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9547 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9548 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9549 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9550 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9551 License Plate Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9552 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9553 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9554 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9555 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9556 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9557 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9558 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9559 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9560 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9561 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9562 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9563 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9564 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9565 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9566 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9567 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9568 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9569 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9570 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9571 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9572 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9573 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9574 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9575 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9576 License Plate Lamp: Electrical Diagrams Front Marker/Hazard/Park/Turn/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9577 Turn/Stop/Hazard/High Mounted Stop/Front Marker/Park/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9578 Tail/Rear Marker/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > License Plate Lamp > Component Information > Diagrams > Page 9579 License Plate Lamp: Description and Operation Voltage is applied at all times from I/P Fuse #31 to the Headlamp Switch and, if equipped, to the Automatic Headlamp Control or Daytime Running Lamp (DRL) Module from CKT 240. With the Headlamp Switch in "PARK" or "HEAD" or with low light conditions, if equipped with Twilight Sentinel, voltage is applied to CKT 9. Current flows through CKT 9, to I/P Fuse Block, which feeds all Park, Marker, Tail and License Lamps turning them "ON." The only lamps that see a current from CKT 308 and do not turn "ON," are the turn filaments in the Park/Turn Lamps. They do not activate because the voltage drop across the Front Side Marker Lamps is much higher than that across the Turn Lamp Filaments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Map Light > Component Information > Locations > RH RH Hood Rail Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Map Light > Component Information > Locations > RH > Page 9584 Front Headliner Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear Marker Lamp: Locations Marker Lamp, Rear LH LH Rear of Vehicle RH RH Rear of Vehicle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9589 Marker Lamp: Locations Park and Side Marker Lamp, Front LH Forward Lamp Wiring RH Forward Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9590 LH Forward Lamp Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9591 Marker Lamp: Locations Side Marker Lamp, LH Rear LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9592 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9593 Marker Lamp: Locations LH LH Rear of Vehicle RH RH Rear of Vehicle LH Forward Lamp Wiring RH Forward Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9594 LH Forward Lamp Wiring LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9595 Rear Lamps RH Forward Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Locations > Marker Lamp, Rear > Page 9596 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions Marker Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9599 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9600 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9601 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9602 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9603 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9604 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9605 Marker Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9606 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9607 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9608 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9609 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9610 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9611 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9612 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9613 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9614 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9615 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9616 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9617 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9618 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9619 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9620 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9621 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9622 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9623 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9624 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9625 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9626 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9627 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9628 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9629 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9630 Marker Lamp: Electrical Diagrams Front Marker/Hazard/Park/Turn/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9631 Turn/Stop/Hazard/High Mounted Stop/Front Marker/Park/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9632 Tail/Rear Marker/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Marker Lamp > Component Information > Diagrams > Page 9633 Marker Lamp: Description and Operation Voltage is applied at all times from I/P Fuse #31 to the Headlamp Switch and, if equipped, to the Automatic Headlamp Control or Daytime Running Lamp (DRL) Module from CKT 240. With the Headlamp Switch in "PARK" or "HEAD" or with low light conditions, if equipped with Twilight Sentinel, voltage is applied to CKT 9. Current flows through CKT 9, to I/P Fuse Block, which feeds all Park, Marker, Tail and License Lamps turning them "ON." The only lamps that see a current from CKT 308 and do not turn "ON," are the turn filaments in the Park/Turn Lamps. They do not activate because the voltage drop across the Front Side Marker Lamps is much higher than that across the Turn Lamp Filaments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement Parking Lamp: Technical Service Bulletins Lighting - Exterior Lamp Condensation and Replacement INFORMATION Bulletin No.: 01-08-42-001H Date: January 05, 2011 Subject: Exterior Lamp Condensation and Replacement Guidelines Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) Supercede: This bulletin is being revised to add the 2011 model year. Please discard Corporate Bulletin Number 01-08-42-001G (Section 08 - Body and Accessories). The following information is being provided to better define the causes of condensation in exterior lamps and includes guidelines for determining the difference between a lamp with a normal atmospheric condition (condensation) and a lamp with a water leak. Some exterior lamps, such as cornering, turn signal, backup, headlamps or tail lamps may exhibit very small droplets of water, a fine mist or white fog (condensation) on the inside of the lamp lens. This may be more noticeable on lamps with "multi-lens" designs and may be normal during certain weather conditions. Condensation occurs when the air inside the lamp assembly, through atmospheric changes, reaches the "dew point". When this takes place, the moisture in the air within the lamp assembly condenses, creating a fine mist or white fog on the inside surface of the lamp lens. Most exterior lamps on General Motors vehicles use a vented design and feature a replaceable bulb assembly. They are designed to remove any accumulated moisture vapor by expelling it through a vent system. The vent system operates at all times, however, it is most effective when the lamps are ON or when the vehicle is in motion. Depending on the size, shape and location of the lamp on the vehicle, and the atmospheric conditions occurring, the amount of time required to clear the lamp may vary from 2 to 6 hours. Completely sealed headlamp assemblies (sealed beams) are still used on a limited number of models being manufactured today. These lamps require the replacement of the complete lamp assembly if a bulb filament burns out. Condensation 2006 TrailBlazer Shown A Fine Mist or White Fog on the Inside Surface of the Lamp Lens Occurring After a Period of High Humidity - May be located primarily in the lens corners (near the vents) and SHOULD NOT cover more than half the lens surface. - The condition should clear of moisture when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a SIMILAR performance. If the above conditions are noted, the customer should be advised that replacement of a lamp assembly may not correct this condition. Water Leak New Style Pickup Shown Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement > Page 9638 Numerous & Various Size Drops of Water Collecting on the Inside Surface of the Lamp Lens After the Vehicle Has Been Exposed to Rain or a Car Washing Environment - A condition that covers more than half the surface of the lamp lens. - An accumulation of water in the bottom of the lamp assembly. - A condition that WON'T clear when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a different performance. Any of the above conditions would indicate the need to service the lens or lamp assembly. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Locations > LH LH Forward Lamp Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Locations > LH > Page 9641 RH Forward Engine Compartment Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions Parking Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9644 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9645 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9646 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9647 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9648 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9649 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9650 Parking Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9651 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9652 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9653 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9654 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9655 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9656 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9657 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9658 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9659 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9660 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9661 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9662 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9663 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9664 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9665 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9666 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9667 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9668 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9669 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9670 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9671 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9672 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9673 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9674 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9675 Parking Lamp: Electrical Diagrams Front Marker/Hazard/Park/Turn/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9676 Turn/Stop/Hazard/High Mounted Stop/Front Marker/Park/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Parking Lamp > Component Information > Diagrams > Page 9677 Parking Lamp: Description and Operation Voltage is applied at all times from I/P Fuse #31 to the Headlamp Switch and, if equipped, to the Automatic Headlamp Control or Daytime Running Lamp (DRL) Module from CKT 240. With the Headlamp Switch in "PARK" or "HEAD" or with low light conditions, if equipped with Twilight Sentinel, voltage is applied to CKT 9. Current flows through CKT 9, to I/P Fuse Block, which feeds all Park, Marker, Tail and License Lamps turning them "ON." The only lamps that see a current from CKT 308 and do not turn "ON," are the turn filaments in the Park/Turn Lamps. They do not activate because the voltage drop across the Front Side Marker Lamps is much higher than that across the Turn Lamp Filaments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Courtesy Lamp Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Daytime Running Lamp Control Unit > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Daytime Running Lamp Control Unit > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 9686 RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Daytime Running Lamp Control Unit > Component Information > Locations > Page 9687 Daytime Running Lamp Control Unit: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Daytime Running Lamp Relay > Component Information > Diagrams Theft Deterrent Relay Daytime Running Lamps (DRL) Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 9695 RH Lower Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Daytime Running Lamp (DRL)/Twilight Module > Page 9696 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Page 9697 Headlamp Control Module: Diagrams DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C2 DRL Control Module, Keyless Entry Receiver & Twilight Sentinel Module: C1 Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Headlamp Control Module > Component Information > Locations > Page 9698 Headlamp Control Module (C2) C406: Body Harness To Tailgate Harness, Headlamp Automatic Control Module (C1), Remote Control Door Lock Receiver Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Relays and Modules - Lighting and Horns > Horn Relay > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Ambient Light Sensor > Component Information > Locations Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Backup Lamp Switch > Component Information > Locations Backup Lamp Switch: Locations RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Backup Lamp Switch > Component Information > Locations > Page 9709 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Brake Light Switch > Component Information > Locations Brake Light Switch: Locations LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Brake Light Switch > Component Information > Locations > Page 9713 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Brake Light Switch > Component Information > Locations > Page 9714 Brake Light Switch: Service and Repair The stop light switch has a slip fit in the mounting sleeve which permits positive adjustment by pulling the brake pedal up firmly against the stop. The pedal arm forces the switch body to slip in the mounting sleeve bushing to position the switch properly. 1. Disconnect wires from switch and remove switch from bracket. 2. Position replacement switch in bracket and push inward until fully seated. Brake pedal arm moves switch to correct distance on rebound. Check if pedal is in full return position by lifting slightly by hand. 3. Connect switch electrical connector. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front LH Side Of Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9719 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9720 Door Switch: Locations Door Jamb Switch, RH Front Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9721 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Door Switch > Component Information > Locations > Door Jamb Switch, LH Front > Page 9722 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Headlamp Dimmer Switch > Component Information > Locations Upper LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector Twilight Sentinel Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 9730 Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 9731 Headlamp Switch: Locations Twilight Sentinel/Daytime Running Lamps Harness Back View Of RH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Twilight Sentinel Connector > Page 9732 Center Of Instrument Panel Wiring Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Page 9733 Headlamp Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Headlamp Switch > Component Information > Locations > Page 9734 Headlamp Switch: Service and Repair Fig. 7 Headlamp Switch Replacement 1. Disconnect battery ground cable. 2. Remove lower steering column trim panel attaching screws, then pull downward to remove. 3. Through glove compartment, unsnap righthand molding. 4. Loosen steering column support bracket to instrument panel carrier attaching bolts. Do not remove bolts. 5. Gently lower steering column assembly. Use extreme care when lowering steering to prevent damage to column assembly. 6. Remove lefthand trim plate to instrument panel carrier assembly six attaching screws, then unsnap lefthand trim assembly. 7. Remove headlamp switch attaching screws. 8. Pull switch rearward, then disconnect switch electrical connectors and remove, Fig. 7. 9. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Horn Switch > Component Information > Locations Steering Wheel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch Trunk Lid With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch > Page 9742 Rear Luggage Compartment With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch > Page 9743 Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations Turn Signal Switch: Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 9747 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 9748 C210: Turn Signal Switch Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 9749 Turn Signal Switch: Service and Repair Fig. 9 Lock Plate Retaining Ring Removal Fig. 10 Turn Signal Electrical Connector & Wiring Isolation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Sensors and Switches - Lighting and Horns > Turn Signal Switch > Component Information > Locations > Page 9750 Fig. 11 Turn Signal Switch Removal From Column Bowl Fig. 12 Turn Signal Switch Replacement 1. Disconnect battery cable, then remove steering wheel and column to instrument panel trim cover. 2. On models with telescoping column, remove bumper spacer and snap ring retainer. 3. On models less telescoping column, remove cover from lock plate. 4. On all models, using a suitable tool, compress lock plate (horn contact carrier on tilt models) and remove snap ring (C-ring on tilt models), Fig. 9. 5. Remove lock plate, cancelling cam, upper bearing preload spring, thrust washer and signal lever. 6. Remove turn signal lever or actuating arm screw, if equipped, or on models with column mounted wiper switch, pull lever straight out of detent. Depress hazard warning button, then unscrew button. 7. Pull connector from bracket and wrap upper part of connector with tape to prevent snagging wires during removal, Fig. 10. 8. On Tilt models, position shifter housing in Low position. Remove harness cover. 9. On models less tilt remove retaining screws and remove switch, Fig. 11 AND 12. 10. Reverse procedure to install Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement Tail Lamp: Technical Service Bulletins Lighting - Exterior Lamp Condensation and Replacement INFORMATION Bulletin No.: 01-08-42-001H Date: January 05, 2011 Subject: Exterior Lamp Condensation and Replacement Guidelines Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) Supercede: This bulletin is being revised to add the 2011 model year. Please discard Corporate Bulletin Number 01-08-42-001G (Section 08 - Body and Accessories). The following information is being provided to better define the causes of condensation in exterior lamps and includes guidelines for determining the difference between a lamp with a normal atmospheric condition (condensation) and a lamp with a water leak. Some exterior lamps, such as cornering, turn signal, backup, headlamps or tail lamps may exhibit very small droplets of water, a fine mist or white fog (condensation) on the inside of the lamp lens. This may be more noticeable on lamps with "multi-lens" designs and may be normal during certain weather conditions. Condensation occurs when the air inside the lamp assembly, through atmospheric changes, reaches the "dew point". When this takes place, the moisture in the air within the lamp assembly condenses, creating a fine mist or white fog on the inside surface of the lamp lens. Most exterior lamps on General Motors vehicles use a vented design and feature a replaceable bulb assembly. They are designed to remove any accumulated moisture vapor by expelling it through a vent system. The vent system operates at all times, however, it is most effective when the lamps are ON or when the vehicle is in motion. Depending on the size, shape and location of the lamp on the vehicle, and the atmospheric conditions occurring, the amount of time required to clear the lamp may vary from 2 to 6 hours. Completely sealed headlamp assemblies (sealed beams) are still used on a limited number of models being manufactured today. These lamps require the replacement of the complete lamp assembly if a bulb filament burns out. Condensation 2006 TrailBlazer Shown A Fine Mist or White Fog on the Inside Surface of the Lamp Lens Occurring After a Period of High Humidity - May be located primarily in the lens corners (near the vents) and SHOULD NOT cover more than half the lens surface. - The condition should clear of moisture when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a SIMILAR performance. If the above conditions are noted, the customer should be advised that replacement of a lamp assembly may not correct this condition. Water Leak New Style Pickup Shown Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement > Page 9755 Numerous & Various Size Drops of Water Collecting on the Inside Surface of the Lamp Lens After the Vehicle Has Been Exposed to Rain or a Car Washing Environment - A condition that covers more than half the surface of the lamp lens. - An accumulation of water in the bottom of the lamp assembly. - A condition that WON'T clear when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a different performance. Any of the above conditions would indicate the need to service the lens or lamp assembly. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9758 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9759 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9760 LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9761 Tail Lamp: Locations LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9762 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9763 Rear Lamps LH Taillamp Harness (Wagon) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9764 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Locations > Tail/Turn/Stoplamp, Lower > Page 9765 Rear Lamps Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions Tail Lamp: Diagram Information and Instructions Abbreviation A/C Air Conditioning CCM Central Control Module CKT Circuit CONN Connector EBCM Electronic Brake Control Module EBTCM Electronic Brake and Traction Control Module ECM Engine Control Module HARN Harness I/P Instrument Panel LH Left Hand PCM Powertrain Control Module RH Right Hand TERM Terminal Body Part Names Cell References CELL REFERENCES General Motors vehicles often use "CELL" references in their electrical wiring diagrams. These references are used in the Original Equipment Manual to refer to a section in the manual and not a specific diagram(s). Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9768 GM Sample Diagram W/ Cell Reference For instance, in the diagram illustrated "Cell 20" is not a reference to another diagram but a reference to "Section 20" in the OE manual. In the example, "Section 20" is the engine control section of the manual. To navigate through these "Cell" references start at the vehicle level and go to: Diagrams / Electrical Diagrams - for a complete list of the diagrams available for the vehicle. Choose the system you are working on and view those diagrams. Note: If unsure of the system - try utilizing the search feature. Type a component in the search feature that belongs to the system and when the results are displayed note the path displayed. This will show the system the component belongs in. Electrostatic Discharge (ESD Sensitive Devices) All Electrostatic Discharge (ESD) sensitive components are Solid State and the following information applies to them. ESD Symbol Typical Schematic Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9769 The ESD symbol is used on schematics to indicate which components are ESD sensitive. When handling any electronic part, the service technician should follow the guidelines below to reduce any possible electrostatic charge build-up on the service technician's body and inadvertent discharge to the electronic part. If it is not known whether or not a component is ESD sensitive, assume it is susceptible. Handling Procedures 1. Always touch a known good ground before handling the part. This should be repeated while handling the pan and more frequently after sliding across a seat, sitting down from a standing position or walking a distance. 2. Avoid touching electrical terminals of the part, unless so instructed by a written diagnostic procedure. 3. When using a voltmeter, be sure to connect the ground lead first. 4. Do not remove a part from its protective package until it is time to install the part. 5. Before removing the part from its package, ground the package to a known good ground on the vehicle. Measuring Procedures The circuits shown within the boxes are greatly simplified. Do not troubleshoot by measuring resistance at any terminal of these devices unless so instructed by a written diagnostic procedure. Due to the simplification of the schematics, resistance measurements could be misleading, or could lead to electrostatic discharge. Schematic Symbols Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9770 Fig.1-Symbols (Part 1 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9771 Fig.2-Symbols (Part 2 Of 3) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9772 Fig.3-Symbols (Part 3 Of 3) Vacuum Motors operate like electrical solenoids, mechanically pushing or pulling a shaft between two fixed positions. When vacuum is applied, the shaft is pulled in. When no vacuum is applied, the shaft is pushed all the way out by a spring. Double Diaphragm Motors can be operated by vacuum in two directions. When there is no vacuum, the motor is in the center "at rest" position. Some Vacuum Motors such as the Servo Motor in the Cruise Control can position the actuating arm at any position between fully extended and fully retracted. The servo is operated by a control valve that applies varying amounts of vacuum to the motor. The higher the vacuum level, the greater the retraction of the motor arm. Servo Motors work like the two position motors; the only difference is in the way the vacuum is applied. Servo Motors are generally larger and provide a calibrated control. Supplemental Inflatable Restraint (SIR) System SIR Symbol The Supplemental Inflatable Restraint (SIR) symbol is used on schematics to alert the technician to the following important caution. CAUTION: This vehicle is equipped with SIR. Refer to CAUTIONS in SIR under Air Bags and Seat Belts before performing service on or around SIR components or wiring. Failure to follow CAUTIONS could result in possible air bag deployment, personal injury, or otherwise unneeded SIR system repairs. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9773 Wire Color Code Identification Black: BLK Blue: BLU Brown: BRN Grey: GR Or GRY Green: GRN Natural: NAT Orange: ORN Pink: PNK Purple: PPL Red: RED Tan: TAN White: WHT Yellow: YEL Dark: DK (example: DK GRN same as Dark Green) Light: LT (example: LT BLU same as Light Blue) Wire Size Conversion Table Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9774 Tail Lamp: Diagnostic Aids Additional Information NOTE: Turn OFF power to the test circuit before attempting in-circuit resistance measurements to prevent false readings or damage to the meter. Do not use the meter to measure resistance through a solid state module. Continuity tests that work well for detecting intermittent shorts to ground can be performed by setting the meter to "ohms" then pressing the "PEAK MIN MAX" button. An audible tone will be heard whenever the meter detects continuity for at least 1 millisecond. The J 39200 Instruction Manual is a good source of information and should be read thoroughly upon receipt of the meter as well as kept on hand for reference during new procedures. Basic Knowledge Required Without a basic knowledge of electricity, it will be difficult to use the diagnostic procedures contained in this section. You should understand the basic theory of electricity and know the meaning of voltage, current (amps) and resistance (ohms). You should understand what happens in a circuit with an open or a shorted wire. You should be able to read and understand a wiring diagram. The following four-step troubleshooting procedure is recommended: Step 1: Check the Problem Perform a System Check to determine a symptom. Don't waste time fixing part of the problem! Do not begin disassembly or testing until you have narrowed down the possible causes. Step 2: Read the Electrical Schematic Study the schematic. Read the Circuit Operation text if you do not understand how the circuit should work. Check circuits that share wiring with the problem circuit. (Shared circuits are shown on Power Distribution, Ground Distribution, Fuse Block Details and Light Switch Details.) Try to operate the shared circuits. If the shared circuits work, then the shared wiring is OK. The cause must be within the wiring used only by the problem circuit. If several circuits fail at the same time, chances are the power (fuse) or ground circuit is faulty. Step 3: Find the fault and repair ^ Narrow down the possible causes. ^ Use the Troubleshooting Hints. ^ Make the necessary measurements or checks as given in the System Diagnosis. ^ Before replacing a component, check power, signal and ground wires at the component harness connector. If the checks and connections are OK, the most probable cause is component failure. Step 4: Test the Repair Repeat the System Check to verify that the fault has been corrected and that no other faults were induced during the repair. EXAMPLE: A customer brings in a vehicle and says that the HI beams do not work. Step 1: Perform a System Check on the Headlight Circuit You may discover that both LO beams operate. In HI, you may notice that the HI Beam Indicator comes ON, but neither HI beam operates. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9775 Typical Headlights Schematic Step 2: Read the Headlights Electrical Schematic This is the step that will save time and labor. Remember, it is essential to understand how a circuit should work, before trying to figure out why it doesn't. After you understand how the circuit should operate, read the schematic again, this time keeping in mind what you have learned by operating the circuit. Since both LO beams work, you know that the Headlight Switch, the YEL wire, the LO contacts of the Headlight Dimmer Switch, terminal "IE" of C100, the TAN wires and grounds G1O5 and G109 are all good. Furthermore, since you saw that the HI Beam Indicator came ON when the Headlight Dimmer Switch was moved to HI you know that the HI contacts of the Headlight Dimmer Switch and the LT GRN wire between the Headlight Dimmer Switch and C100 are good. At this point, you could test for voltage at the RH Headlamp with the Headlight Dimmer Switch in HI. However, it is extremely unlikely that the HI beam filaments have burned out in both headlamps, or that both headlamps connections are bad. The cause must be a bad connection at C100, or a break in the LT GRN wire between C100 and the RH Headlamp. You have quickly narrowed the possible causes down to one specific area, and have done absolutely no work on the vehicle itself. Step 3: Find the fault and repair it Using the Component Location List and the corresponding figure, you can quickly find C100 and the LT GRN wire, locate the exact trouble point and make the repair. Step 4: Check the repair by performing a System Check on the Headlights Circuit This, of course, means making sure that both HI beams, both LO beams and the HI Beam Indicator are all working. Now suppose that the symptoms were different. You may have operated the Headlamps and found that the LO beams were working, but neither the HI beams nor the HI Beam Indicator were working. Looking at the schematic, you might conclude that it is unlikely that both HI beam filaments and the HI Beam Indicator have all burned out at once. The cause is probably the Headlight Dimmer Switch or its connector. Checking Terminal Contacts Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9776 DESCRIPTION When diagnosing an electrical system that utilizes Metri-Pack 150/280/480/630 series terminals (refer to Terminal Repair Kit, J 38125-A, J 38125-4 for terminal identification), it is important to check terminal contact between a connector and component, or between in-line connectors, before replacing a suspect component. Frequently, a diagnostic chart leads to a step that reads: Check for poor connection. Mating terminals must be inspected to assure good terminal contact. A poor connection between the male and female terminal at a connector may be the result of contamination or deformation. Contamination is caused by the connector halves being improperly connected, a missing or damaged connector seal, or damage to the connector itself, exposing the terminals to moisture and dirt. Contamination, usually in underhood or underbody connectors, leads to terminal corrosion, causing an open circuit or intermittently open circuit. Deformation Of A Typical Metri-Pack 150/280/480/630 Series Female Terminal Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9777 Deformation is caused by probing the mating side of a connector terminal without the proper adapter, improperly joining the connector halves or repeatedly separating and joining the connector halves. Deformation, usually to the female terminal contact tang, can result in poor terminal contact, causing an open or intermittently open circuit. PROCEDURE Follow the procedure below to check terminal contact. 1. Separate the connector halves. Refer to Terminal Repair Kit, J 38125-A, J 38125-4. 2. Inspect the connector halves for contamination. Contamination will result in a white or green build-up within the connector body or between terminals, causing HI terminal resistance, intermittent contact or an open circuit. An underhood or underbody connector that shows signs of contamination should be replaced in its entirety: terminals, seals and connector body. 3. Using an equivalent male terminal from the Terminal Repair Kit, J 38125-A, check the retention force of the female terminal in question by inserting and removing the male terminal to the female terminal in the connector body. Good terminal contact will require a certain amount of force to separate the terminals. 4. Using an equivalent female terminal from the Terminal Repair Kit, J 38125-A, compare the retention force of this terminal to the female terminal in question by joining and separating the male terminal to the good female terminal, and then joining and separating the male terminal to the female terminal in question. If the retention force is significantly different between the two female terminals, replace the female terminal in question (refer to Terminal Repair Kit, J 38125-A). If a visual (physical) check does not reveal the cause of the problem, the vehicle may be able to be driven with a Digital Voltmeter (DVM) connected to the suspected circuit. An abnormal voltage reading when the problem occurs indicates the problem may be in that circuit. Detecting Electrical Intermittents PROCEDURE Use the following procedure to detect intermittent terminal contact or a broken wire with an intermittent connection inside the insulation. The J 39200 Digital Multimeter has the ability to monitor current, resistance, or voltage while recording the minimum (MIN) and maximum (MAX) values measured. The meter can also be set to display the average (AVG) value measured. When diagnosing circuits that have voltage applied, use the voltage setting to monitor a connector (or length of a circuit) which is suspected of having an intermittent connection but is currently operating normally. 1. Connect the J 39200 Digital Multimeter to both sides of a suspect connector (still connected) or from one end of a suspect circuit to the other. This will continuously monitor the terminal contacts or length of wire being checked. Refer Meter Connections for examples of the various methods for connecting the meter to the circuit. See: General Troubleshooting Procedures/Meter Connections 2. Set the meter for voltage. Since the "MIN MAX" mode does not use auto ranging, manually select the voltage range necessary before proceeding. 3. Press the "MIN MAX" button. The meter should read "100 ms RECORD" (100 millisecond record) and emit a 1/4 second beep. The meter is now ready to record and will generate an audible tone for any change in voltage. At this point, you may wish to press the "PEAK MIN MAX" button, which will record any voltage variations that occur for at least 1 millisecond. 4. Try to simulate the condition that is potentially causing an intermittent connection, either by wiggling connections or wiring, test driving or performing other operations. If an open or resistance is created, a voltage will be present and the meter will emit a tone for as long as the open or resistance exists. Any change in voltage will cause the meter to emit a tone for no less than 1/4 second. (Listening for a tone while manipulating wiring is very helpful for narrowing down an intermittent connection.) Use the MIN and MAX values when the meter is out of sight or sound range, in noisy areas or for test driving when it may not be possible to monitor the meter. To check the MIN and MAX recorded voltages press "MIN MAX" once for MAX and twice for MIN. A variation between MIN and MAX recorded voltages (unless nearly 0 volts) suggests an intermittent open or that resistance exists and should be repaired as necessary. IMPORTANT: The "100 ms RECORD" (100 millisecond record) mode is NOT the amount of time allowed to perform a specific procedure. It is the amount of time used to record each snapshot of information used for calculating "AVG" when in the "MIN MAX" mode. Intermittents and Poor Connections Most intermittents are caused by faulty electrical connections or wiring, although occasionally a sticking relay or solenoid can be a problem. Some items to check are: ^ Poor mating of connector halves, or terminals not fully seated in the connector body (backed out). ^ Dirt or corrosion on the terminals. The terminals must be clean and free of any foreign material which could impede proper terminal contact. ^ Damaged connector body, exposing the terminals to moisture and dirt, as well as not maintaining proper terminal orientation with the component or mating connector. ^ Improperly formed or damaged terminals. All connector terminals in problem circuits should be checked carefully to ensure good contact tension. Use a corresponding mating terminal to check for proper tension. Refer to Checking Terminal Contact for the specific procedure. ^ The J 35616-A Connector Test Adapter Kit must be used whenever a diagnostic procedure requests checking or probing a terminal. Using the adapter will ensure that no damage to the terminal will occur, as well as giving an idea of whether contact tension is sufficient. If contact tension seems incorrect, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts ^ Poor terminal-to-wire connection. Some conditions which fall under this description are poor crimps, poor solder joints, crimping over wire insulation rather than the wire itself, corrosion in the wire-to-terminal contact area, etc. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9778 ^ Wire insulation which is rubbed through, causing an intermittent short as the bare area touches other wiring or parts of the vehicle. ^ Wiring broken inside the insulation. This condition could cause a continuity check to show a good circuit, but if only 1 or 2 strands of a multi-strand type wire are intact, resistance could be far too HI. To avoid any of the above problems when making wiring or terminal repairs, always follow the instructions for wiring and terminal repair outlined under the Repair Procedures. See: Wire Repair Procedures/Typical Electrical Repair Procedures Meter Connections The previous diagnostic procedure was written to detect intermittents using the meter set to voltage. Whether using the current, voltage or resistance setting to detect intermittents, it is necessary to connect the meter to the circuit. Following are examples of the various methods of connecting the meter to the circuit to be checked: ^ Backprobe both ends of the connector and either hold the leads in place while manipulating the connector or tape the leads to the harness for continuous monitoring while performing other operations or test driving. (Do not backprobe "Weather Pack(R)" type connectors.) ^ Disconnect the harness at both ends of the suspect circuit where it connects either to a component or to other harnesses. ^ Use Connector Test Adapter Kit J 35616-A to connect the meter to the circuit. ^ If the system being diagnosed has a specified Pinout or breakout box, it may be used to simplify connecting the meter to the circuit or for checking multiple circuits quickly. Aftermarket Accessories Always check for aftermarket accessories as the first step in diagnosing electrical problems. If the vehicle is so equipped, disconnect the system to verify that these add-on accessories are not the cause of the problems. Some possible causes of vehicle problems related to aftermarket accessories include: 1. Power feeds connected to points other than the Battery. 2. Antenna location. 3. Transceiver wiring located too close to vehicle electronic modules or wiring. 4. Poor shielding or poor connectors on antenna feed line. Probing (Frontprobe & Backprobe) After probing, when reconnecting connectors or replacing terminals, always be sure to reinstall Connector Position Assurance (CPA) and Terminal Position Assurance (TPA). Frontprobe When frontprobing of connectors is required, always use a mating terminal adapter from Connector Test Adapter Kit (J 35616-A). The use of proper adapters will ensure that proper terminal contact integrity is maintained. (refer to Procedures in Checking Terminal Contact). Backprobe Only backprobe connector terminals when specifically called for in diagnostic procedures. Since backprobing can be a source of damage to connector terminals, extra care must be taken to avoid deforming the terminal, either by forcing the test probe too far into the cavity or by using too large a test probe. After backprobing any connector, always check for terminal damage. If terminal damage is suspected, check for proper terminal contact, refer to Checking Terminal Contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Testing For Voltage Voltage Check Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9779 1. Connect one lead of a test light to a known good ground. When using a Digital Voltmeter (DVM), be sure the voltmeter's negative lead is connected to ground. 2. Connect the other lead of the test light or voltmeter to a selected test point (connector or terminal). 3. If the test light illuminates, there is voltage present. When using a DVM, note the voltage reading. Testing For Continuity Continuity Check Through A Switch 1. Remove the fuse to the circuit involved. 2. Connect one lead of a self-powered test light or ohmmeter to one end of the part of the circuit you wish to test. 3. Connect the other lead to the other end of the circuit. 4. If the self-powered test light glows, there is continuity. When using an ohmmeter, LO or no resistance means good continuity. Testing For Voltage Drop Voltage Drop Test This test checks for voltage being lost along a wire, or through a connection or switch. 1. Connect the positive lead of a Digital Voltmeter (DVM) to the end of the wire (or to one side of the connection or switch) which is closer to the Battery. 2. Connect the negative lead to the other end of the wire (or the other side of the connection or switch). 3. Operate the circuit. 4. The DVM will show the difference in voltage between the two points. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9780 Testing For Short to Ground Testing For Short With Self Powered Test Light Or Ohmmeter WITH A TEST LIGHT OR DIGITAL VOLTMETER (DVM) 1. Remove the blown fuse and disconnect the load. 2. Connect a test light or voltmeter across the fuse terminals (be sure that the fuse is powered). 3. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the test light or DVM. 4. When the test light glows, or the DVM registers, there is a short to ground in the wiring near that point. Testing For Short With Test Light Or DVM WITH A SELF-POWERED TEST LIGHT OR OHMMETER. 1. Remove the blown fuse and disconnect the Battery and load. 2. Connect one lead of a self-powered test light or ohmmeter to the fuse terminal on the load side. 3. Connect the other lead to a known good ground. 4. Beginning near the Fuse Block, wiggle the harness from side to side. Continue this at convenient points (about 6 inches apart) while watching the self-powered test light or ohmmeter. 5. When the self-powered test light glows, or the ohmmeter registers, there is a short to ground in the wiring near that point. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9781 FUSES POWERING SEVERAL LOADS 1. Find the schematic under "Fuse Block Details," for the fuse that has blown. 2. Open the first connector or switch leading from the fuse to each load. 3. Replace the fuse. ^ If the fuse blows, the short is in the wiring leading to the first connector or switch. Use a test light or meter as described. ^ If fuse does not blow, refer to next step. 4. Close each connector or switch until the fuse blows in order to find which circuit has the short. Connect test lamp or meter at the connector to the suspect circuit (disconnected) rather than at the fuse terminals. Test Light/Digital Voltmeter Use a test light to check for voltage. A Test Light (J 34l42-B) is made up of a 12 volt light bulb with a pair of leads attached. After grounding one lead, touch the other lead to various points along the circuit where voltage should be present. When the bulb goes ON, there is voltage at the point being tested. A Digital Voltmeter (DVM) can be used instead of a test light. While a test light shows whether or not voltage is present, a DVM indicates how much voltage is present. An increasing number of circuits include solid state control modules. One example is the Engine Control Module (ECM). Voltages in these circuits should be tested only with a 10-megohm or higher impedance DVM or multimeter (J 39200). Unless directed to within the diagnostics, NEVER use a test light on circuits that contain solid state components, since damage to these components may result. When testing for voltage or continuity at the connection, it is not necessary to separate the two halves of the connector. Unless testing a Weather Pack(R) connector, always probe the connector from the back. Always check both sides of the connector. An accumulation of dirt and corrosion between contact surfaces is sometimes a cause of electrical problems. Refer to Procedures in checking terminal contact. See: General Troubleshooting Procedures/Checking Terminal Contacts Connector Test Adapters Connector Test Adapter Kit (J 35616-A) is available for making tests and measurements at separated connectors. This kit contains an assortment of probes which mate with many of the types of terminals you will see. Avoid using paper clips and other substitutes since they can damage terminals and cause incorrect measurements. Self-Powered Test Light A self-powered test light (J 21008-A) can be used to check for continuity. This tool is made up of a light bulb, Battery and two leads. If the leads are touched together, the bulb will go ON. A self-powered test light is used only on an unpowered circuit. First remove the fuse which feeds the circuit you're working on. Select two specific points along the circuit through which there should be continuity. Connect one lead of the self-powered test light to each point. If there is continuity, the test light circuit will be completed and the bulb will go ON. NEVER use a self-powered test light on circuits that contain solid state components, since damage to these components may result. Ohmmeter An ohmmeter can be used instead of a self-powered test light. The ohmmeter shows how much resistance there is between two points along a circuit. LO resistance means good continuity. Circuits which include any solid state control modules, such as the Engine Control Module (ECM), should be tested only with a 10-megohm or higher impedance digital multimeter (J 39200). When measuring resistance with a Digital Voltmeter (DVM), the vehicle Battery should be disconnected. This will prevent incorrect readings. DVMs apply such a small voltage to measure resistance that the presence of voltages can upset a resistance reading. Diodes and solid state components in a circuit can cause an ohmmeter to give a false reading. To find out if a component is affecting a measurement, take a reading once, reverse the leads and take a second reading. If the readings differ, the solid state component is affecting the measurement. Fused Jumper Wire A fused jumper (J 36169) is available with small clamp connectors providing adaptation to most connectors without damage. This fused jumper wire is supplied with a 20 amp fuse which may not be suitable for some circuits. Do not use a fuse with a higher rating than the fuse that protects the circuit being tested. NOTE: A fused jumper may not protect solid state components from being damaged. Short Finder Short Finders (J 8681-A) are available to locate hidden shorts to ground. The short finder creates a pulsing magnetic field in the shorted circuit and shows you the location of the short through body trim or sheet metal. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9782 Fuse Tester A simple tester (J 34764) can detect a blown fuse. To check a fuse, the tester is applied directly to the fuse in the Fuse Block. Two probes contact the fuse, either into the slots of a flat fuse or to the metal ends of a glass fuse. With power ON, a red Light Emitting Diode (LED) in the tester lights if the fuse is open. The handle of the tester is a tool for removing either type of fuse. Special Tools Circuit Breakers A circuit breaker is a protective device designed to open the circuit when a current load is in excess of rated breaker capacity. If there is a short or other type of overload condition in the circuit, the excessive current will open the circuit between the circuit breaker terminals. There are two basic types of circuit breakers used in GM vehicles: cycling and non-cycling. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9783 Cycling Circuit Breaker The cycling breaker will open due to heat generated when excessive current passes through it for a period of time. Once the circuit breaker cools, it will close again after a few seconds. If the cause of the HI current is still present it will open again. It will continue to cycle open and closed until the condition causing the HI current is removed. Non-Cycling Circuit Breaker There are two types of non-cycling circuit breakers. One type is mechanical and is nearly the same as a cycling breaker. The difference is a small heater wire within the non-cycling circuit breaker. This wire provides enough heat to keep the bimetallic element open until the current source is removed. The other type is solid state, called out in this section as Electronic Circuit Breaker (ECB). This device has a Positive Temperature Coefficient. It increases its resistance greatly when excessive current passes through it. The excessive current heats the ECB. As it heats, its resistance increases, therefore having a Positive Temperature Coefficient. Eventually the resistance gets so HI that the circuit is effectively open. The ECB will not reset until the circuit is opened, removing voltage from its terminals. Once voltage is removed, the circuit breaker will re-close within a second or two. Fuses Fuse Devices The most common method of automotive wiring circuit protection is the fuse. A fuse is a device that, by the melting of its element, opens an electrical circuit when the current exceeds a given level for a sufficient time. The action is non-reversible and the fuse must be replaced each time a circuit is overloaded or after a malfunction is repaired. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9784 Fuse Rating And Color Fuses are color coded. The standardized color identification and ratings are shown. For service replacement, non-color coded fuses of the same respective current rating can be used. Examine a suspect fuse for a break in the element. If the element is broken or melted, replace the fuse with one of equal current rating. There are additional specific circuits with in-line fuses. These fuses are located within the individual wiring harness and will appear to be an open circuit if blown. Autofuse The Autofuse, normally referred to simply as "Fuse," is the most common circuit protection device in today's vehicle. The Autofuse is most often used to protect the wiring assembly between the Fuse Block and the system components. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9785 Maxifuse The Maxifuse was designed to replace the fusible link and Pacific Fuse elements. The Maxifuse is designed to protect cables, normally between the battery and fuse block, from both direct short circuits and resistive short circuits. Compared to a fusible link or a Pacific Fuse element, the Maxifuse performs much more like an Autofuse, although the average opening time is slightly longer. This is because the Maxifuse was designed to be a slower blowing fuse, with less chance of nuisance blows. Minifuse The Minifuse is a smaller version of the Autofuse and has a similar performance. As with the Autofuse, the Minifuse is usually used to protect the wiring assembly between a fuse block and system components. Since the Minifuse is a smaller device, it allows for more system specific fusing to be accomplished within the same amount of space as Autofuses. Pacific Fuse Element/Maxifuse The Pacific Fuse Element and Maxifuse were developed to be a replacement for the fusible link. Like a fusible link, the fuses are designed to protect wiring from a direct short to ground. These elements are easier to service and inspect than a fusible link and will eventually replace fusible links in all future vehicle applications. Fusible Links Good And Damaged Fusible Links In addition to circuit breakers and fuses, some circuits use fusible links to protect the wiring. Like fuses, fusible links are "one-time" protection devices that will melt and create an open circuit. Not all fusible link open Circuits can be detected by observation. Always inspect that there is battery voltage past the fusible link to verify continuity. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9786 Wire Size Conversion Table Fusible links are used instead of a fuse in wiring circuits that are not normally fused, such as the ignition circuit. For AWG sizes, each fusible link is four wire gage sizes smaller than the wire it is designed to protect. For example: to protect a 10 gage wire use a 14 gage link or for metric, to protect a 5 mm Sq. wire use a 2 mm Sq. link, refer to Wire Size Conversion Table. Links are marked on the insulation with wire-gage size because the heavy insulation makes the link appear to be a heavier gage than it actually is. The same wire size fusible link must be used when replacing a blown fusible link. Fusible links are available with three types of insulation: Hypalon(R), Silicone/GXL (SIL/GXL) and Expanded Duty. All future vehicles that use fusible links will utilize the Expanded Duty type of fusible link. When servicing fusible links, all fusible links can be replaced with the Expanded Duty type. SIL/GXI fusible links can be used to replace either SIL/GXI or Hypalon(R) fusible links. Hypalon(R) fusible links can only be used to replace Hypalon(R) fusible links. Determining characteristics of the types of fusible links are: Hypalon(R) (limited use): only available in 0.35 mm Sq. or smaller and its insulation is one color all the way through. - SIL/GXL (widely used): available in all sizes and has a white inner core under the outer color of insulation. - Expanded Duty: available in all sizes, has an insulation that is one color all the way through and has three dots following the writing on the insulation. Service fusible links are available in many lengths. Choose the shortest length that is suitable. If the fusible link is to be cut from a spool, it should be cut 150-225 mm (approx. 6-9 in.) long. NEVER make a fusible link longer than 225 mm (approx. 9 in.). CAUTION: Fusible links cut longer than 225 mm (approx. 9 in.) will not provide sufficient overload protection. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9787 Single Wire Feed Fusible Link To replace a damaged fusible link, cut it off beyond the splice. Replace with a repair link. When connecting the repair link, strip wire and use staking-type pliers to crimp the splice securely in two places. For more details on splicing procedures, refer to "Typical Electrical Repair Procedures." Use crimp and seal splices whenever possible. See: Wire Repair Procedures/Typical Electrical Repair Procedures Double Wire Feed Fusible Link To replace a damaged fusible link which feeds two harness wires, cut them both off beyond the splice. Use two repair links, one spliced to each harness wire. General Information The purpose of circuit protection is to protect the wiring assembly during normal and overload conditions. An overload is defined as a current requirement that is higher than normal. This overload could be caused by a short circuit or system malfunction. The short circuit could be the result of a pinched or cut wire or an internal device short circuit, such as an electronic module failure. The circuit protection device is only applied to protect the wiring assembly, and not the electrical load at the end of the assembly. For example, if an electronic component short circuits, the circuit protection device will assure a minimal amount of damage to the wiring assembly. However, it will not necessarily prevent damage to the component. There are three basic types of circuit protection devices: Circuit Breaker, Fuse and Fusible Link. Diode Replacement Many vehicle electrical systems use a diode to isolate circuits and protect the components from voltage spikes. When installing a new diode, use the following procedure: Step 1: Open the Harness If the diode is taped to the harness, remove all of the tape. Step 2: Remove inoperative Diode Paying attention to current flow direction, remove inoperative diode from the harness with a suitable soldering tool. If the diode is located next to a connector terminal, remove the terminal(s) from the connector to prevent damage from the soldering tool. Step 3: Strip the Insulation Carefully strip away a section of insulation next to the old soldered portion of the wire(s). Do not remove any more than is needed to attach the new diode. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9788 Diode Identification Step 4: Install New Diode Check current flow direction of the new diode, being sure to install the diode with correct bias. Refer the image for replacement diode symbols and current flow explanations. Attach the new diode to the wire(s) using 60/40 rosin core solder. Use a beat sink (aluminum alligator clip) attached across the diode wire ends to protect the diode from excess heat. Follow the manufacturer's instructions for the soldering equipment you are using. Step 5: Install Terminal(s) Install terminal(s) into the connector body if previously removed in Step 2. Step 6: Tape Diode to Harness Tape the diode to the harness or connector using electrical tape. To prevent shorts to ground and water intrusion, completely cover all exposed wire and diode attachment points. Acceptable Diode Replacements In the event 1 amp, 50 PIV (Peak Inverse Rating) diodes are unavailable, a universal diode with a 1 amp, 400 PIV rating can be used for the following applications: ^ A/C Compressor Clutch ^ ABS/4WAL (the ABS Diode on the Delco Moraine is hidden inside of an electrical connector under the carpet at the RH panel) ^ Wiper ^ Charging System (hidden in wire harness) ^ Parking Brake (vehicle with ABS) ^ Relays ^ Solenoids ^ Diesel Glow Plug Circuit General Information OPEN CIRCUIT An open circuit is an incomplete circuit. Power cannot reach the load or reach ground. If a circuit is open, active components do not energize. SHORT CIRCUIT A short circuit is an unwanted connection between one part of the circuit and either ground or another part of the circuit. A short circuit causes a fuse to blow or a circuit breaker to open. Heated Oxygen Sensor (O2S) Repair Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9789 If the Heated Oxygen Sensor pigtail wiring, connector or terminal is damaged, the entire Oxygen Sensor Assembly must be replaced. Do not attempt to repair the wiring, connector or terminals. In order for the sensor to function properly, it must have provided to it a clean air reference. This clean air reference is obtained by way of the Oxygen Sensor signal and heater wires. Any attempt to repair the wires, connectors or terminals could result in the obstruction of the air reference and degraded Oxygen Sensor performance. The following guidelines should be used when servicing the Heated Oxygen Sensor: ^ Do not apply contact cleaner or other materials to the sensor or vehicle harness connectors. These materials may get into the sensor causing poor performance. Also the sensor pigtail and harness wires must not be damaged in such a way that the wires inside are exposed. This could provide a path for foreign materials to enter the sensor and cause performance problems. ^ Neither the sensor or vehicle lead wires should be bent sharply or kinked. Sharp bends, kinks, etc., could block the reference air path through the lead wire. ^ Do not remove or defeat the Oxygen Sensor ground wire (where applicable). Vehicles that utilize the ground wired sensor may rely on this ground as the only ground contact to the sensor. Removal of the ground wire will also cause poor engine performance. ^ To prevent damage due to water intrusion, be sure that the peripheral seal remains intact on the vehicle harness connector. The Engine Harness may be repaired using Packard's Crimp and Splice Seals Terminal Repair Kit J 38125-A. Under no circumstances should repairs be soldered since this could result in the air reference being obstructed. General Information ^ The following general repair procedures can be used to repair most types of connectors. The repair procedures are divided into three general groups: Push-to-Seat, Pull-to-Seat and Weather Pack(R). ^ Use the proper Pick(s) or Tool(s) that apply to the terminal. ^ The Terminal Repair Kit (J 38125-A) contains further information. Push-to-Seat and Pull-to-Seat Connectors Typical Push-to-seat Connector And Terminal Typical Pull-to-seat Connector And Terminal Follow the steps below to repair Push-to-Seat or Pull-to-Seat connectors. The steps are illustrated with typical connectors. Your connector may differ, but the repair steps are similar. Some connectors do not require all the steps shown. Skip those that don't apply. Step 1: Remove any Connector Position Assurance (CPA) Locks . CPAs are designed to retain connectors when mated. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9790 Step 2: Remove any Terminal Position Assurance (TPA) Locks. TPAs are designed to keep the terminal from backing out of the connector. NOTE: The TPA must be removed prior to terminal removal and must be replaced when the terminal is repaired and reseated. Step 3: Open any secondary locks. A secondary lock aids in terminal retention and is usually molded to the connector. Step 4: Separate the connector halves and back out seals. Step 5: Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 6: Locate the terminal lock tang in the connector canal. Step 7: Insert the proper size pick (refer to Terminal Repair kit J 38125-A) straight into the connector canal at the mating end of the connector. Step 8: Depress the locking tang to unseat the terminal. ^ Push-to-Seat - Gently pull on the lead to remove the terminal through the back of the connector. ^ Pull-to-Seat - Gently push on the lead to remove the terminal through the front of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 9: Inspect terminal and connector for damage. Repair as necessary (refer to Terminal Repairs). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 10: Reform lock tang and reseat terminal in connector body. Apply grease if connector was originally equipped with grease. Step 11: Install any CPAs or TPAs, close any secondary locks and join connector halves. Weather Pack(R) Connectors Typical Weather Pack(R) Connector And Terminal Follow the steps below to repair Weather Pack(R) connectors. Step 1: Separate the connector halves. Step 2: Open secondary lock. A secondary lock aids in terminal retention and is usually molded to the connector. Step 3: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9791 Grasp the lead and push the terminal to the forward most position. Hold the lead at this position. Step 4: Insert the Weather Pack(R) terminal removal tool into the front (mating end) of the connector cavity until it rests on the cavity shoulder. Step 5: Gently pull on the lead to remove the terminal through the back of the connector. NOTE: NEVER use force to remove a terminal from a connector. Step 6: Inspect the terminal and connector for damage. Repair as necessary (refer to Terminal Repair). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Terminal Repairs Step 7: Re-form the lock tang and reseat terminal in connector body. Step 8: Close secondary locks and join connector halves. Repairing Short Circuits Caused By Damaged Wire ^ Locate the damaged wire. ^ Find and correct the cause of the wire insulation damage. ^ For minor damage, tape over the wire. If damage is more extensive, replace the faulty segment of the wire (refer to the Splicing Instructions for copper or shielded cable for the correct splicing procedure). See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Splice Clips See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Copper Wire Using Crimp and Seal Splice Sleeves See: Wire Repair Procedures/Typical Electrical Repair Procedures/Splicing Twisted/Shielded Cable Splicing Copper Wire Using Crimp and Seal Splice Sleeves Crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial to form a one-to-one splice. They are to be used where there are special requirements such as moisture sealing. Crimp and seal splice sleeves are included in the J 38125-A Terminal Repair Kit. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). The crimp and seal splice sleeves may be used on all types of insulation except Tefzel and coaxial and may only be used to form a one-to-one splice. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of wire later if you decide to cut more wire to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. This will help prevent moisture from bridging adjacent splices and causing damage. Wire Size Conversion Table Step 3: Strip the Insulation If it is necessary to add a length of wire to the existing harness, be certain to use the same size as the original wire. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9792 To find the correct wire size either find the wire on the schematic and convert the metric size to the equivalent AWG size or use an AWG wire gage. If unsure about the wire size, begin with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Strip approximately 7.5 mm (5/16 in.) of insulation from each wire to be spliced. Be careful to avoid nicking or cutting any of the wires. Check the stripped wire for nicks or cut strands. If the wire is damaged, repeat this procedure after removing the damaged section. Crimp And Seal Splice Sleeve Chart Step 4: Select and Position the Splice Sleeve Select the proper splice sleeve according to wire size. The splice sleeves and tool tests are color coded (refer to Chart). Hand Crimp Tool Using the J 38125-8 splice crimp tool, position the splice sleeve in the proper color nest of the hand crimp tool. Place the splice sleeve in the nest so that the crimp falls midway between the end of the barrel and the stop. Seal Splice Sequence The sleeve has a stop in the middle of the barrel to prevent the wire from going further. Close the hand crimper handles slightly to hold the splice sleeve firmly in the proper nest. Step 5: Insert Wires into Splice Sleeve and Crimp Insert the wire into the splice sleeve until it hits the barrel stop and close the handles of the J 38125-8 crimper tightly until the crimper handles open when released. The crimper handles will not open until the proper amount of pressure is applied to the splice sleeve. Repeat steps 4 and 5 for opposite end of the splice. Step 6: Shrink the Insulation Around the Splice Using the Ultratorch J 38125-5 (follow instructions that accompany Ultratorch), apply heat where the barrel is crimped. Gradually move the heat Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9793 barrel to the open end of the tubing, shrinking the tubing completely as the heat is moved along the insulation. A small amount of sealant will come out of the end of the tubing when sufficient shrinking is achieved. Splicing Copper Wire Using Splice Clips Splice clips are included in the J 38125-A Terminal Repair Kit. The splice clip is a general purpose wire repair device. It may not be acceptable for applications having special requirements such as moisture sealing. Step 1: Open the Harness If the harness is taped, remove the tape. To avoid wire insulation damage, use a sewing "seam ripper" to cut open the harness (available from sewing supply stores). If the harness has a black plastic conduit, simply pull out the desired wire. Step 2: Cut the Wire Begin by cutting as little wire off the harness as possible. You may need the extra length of the wire later if you decide to cut more wire off to change the location of a splice. You may have to adjust splice locations to make certain that each splice is at least 40 mm (1.5 in.) away from other splices, harness branches or connectors. Wire Size Conversion Table Step 3: Strip the Insulation When replacing a wire, use a wire of the same size as the original wire or larger. The schematics list wire size in metric units. The table shows the commercial AWG wire sizes that can be used to replace each metric wire size. Each AWG size is either equal to or larger than the equivalent metric size. To find the correct wire size either find the wire on the schematic page and convert the metric size to the AWG size, or use an AWG wire gage. If you aren't sure of the wire size, start with the largest opening in the wire stripper and work down until a clean strip of the insulation is removed. Be careful to avoid nicking or cutting any of the wires. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9794 Entering The Splice Clip Step 4: Crimp the Wires Select the proper clip to secure the splice. To determine the proper clip size for the wire being spliced, follow the directions included in the J 38125-A Terminal Repair Kit. Select the correct anvil on the crimper. (On most crimpers your choice is limited to either a small or large anvil.) Overlap the stripped wire ends and hold them between your thumb and forefinger as shown. Then, center the splice clip under the stripped wires and hold it in place. ^ Open the crimping tool to its full width and rest one handle on a firm flat surface. ^ Center the back of the splice clip on the proper anvil and close the crimping tool to the point where the former touches the wings of the clip. Crimping The Splice Clip ^ Make sure that the clip and wires are still in the correct position. Then, apply steady pressure until the crimping tool closes. ^ Before crimping the ends of the clip, be sure that: The wires extend beyond the clip in each direction. - No strands of wire are cut loose. - No insulation is caught under the clip. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9795 Completing The Crimp Crimp the splice again, once on each end. Do not let the crimping tool extend beyond the edge of the clip or you may damage or nick the wires. Applying The Solder Step 5: Solder Apply 60/40 rosin core solder to the opening in the back of the clip. Follow the manufacturer's instruction for the solder equipment you are using. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9796 Proper First Taping Step 6: Tape the Splice Center and roll the splicing tape. The tape should cover the entire splice. Roll on enough tape to duplicate the thickness of the insulation on the existing wires. Do not flag the tape. Flagged tape may not provide enough insulation, and the flagged ends will tangle with the other wires in the harness. Proper Second Taping If the wire does not belong in a conduit or other harness covering, tape the wire again. Use a winding motion to cover the first piece of tape. Splicing Twisted/Shielded Cable Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9797 Twisted/shielded Cable Twisted/shielded cable is sometimes used to protect wiring from electrical noise (stray signals). For example, two-conductor cable of this construction is used between the Engine Control Module (ECM) and the distributor. Step 1: Remove Outer Jacket Remove the outer jacket and discard it. Be careful to avoid cutting into the drain wire or the mylar tape. Step 2: Unwrap the Tape Unwrap the aluminium/mylar tape, but do not remove it. The tape will be used to rewrap the twisted conductors after the splices have been made. The Untwisted Conductors Step 3: Prepare the Splice Untwist the conductors. Then, prepare the splice by following the splicing instructions for copper wire presented earlier. Remember to stagger splices to avoid shorts. Step 4: Re-assemble the Cable After you have spliced and taped each wire, rewrap the conductors with the mylar tape. Be careful to avoid wrapping the drain wire in the tape. The Re-assembled Cable Next, splice the drain wire following the splicing instructions for copper wire. Then, wrap the drain wire around the conductors and mylar tape. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9798 Proper Taping Step 5: Tape the Cable Tape over the entire cable using a winding motion. This tape will replace the section of the jacket you removed to make the repair. Terminal Repairs Terminal Repair The following repair procedures can be used to repair Push-to-Seat, Pull-to-Seat or Weather Pack(R) terminals. Some terminals do not require all steps shown. Skip those that don't apply. The Terminal Repair Kit (J 38125-A) contains further information. Step 1: Cut off terminal between core and insulation crimp (minimize wire loss) and remove seal for Weather Pack(R) terminals. Step 2: Apply correct seal per gauge size of wire and slide back along wire to enable insulation removal (Weather Pack(R) terminals only). Step 3: Remove insulation. Step 4: Align seal with end of cable insulation (Weather Pack(R) terminals only). Step 5: Position strip (and seal for Weather Pack(R)) in terminal. Step 6: Hand crimp core wings. Step 7: Hand crimp insulation wings (non-Weather Pack(R)). Hand crimp insulation wings around seal and cable (Weather Pack(R)). Step 8: Solder all hand crimped terminals. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Diagram Information and Instructions > Page 9799 Tail/Rear Marker/License Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Tail Lamp > Component Information > Diagrams > Page 9800 Tail Lamp: Description and Operation Voltage is applied at all times from I/P Fuse #31 to the Headlamp Switch and, if equipped, to the Automatic Headlamp Control or Daytime Running Lamp (DRL) Module from CKT 240. With the Headlamp Switch in "PARK" or "HEAD" or with low light conditions, if equipped with Twilight Sentinel, voltage is applied to CKT 9. Current flows through CKT 9, to I/P Fuse Block, which feeds all Park, Marker, Tail and License Lamps turning them "ON." The only lamps that see a current from CKT 308 and do not turn "ON," are the turn filaments in the Park/Turn Lamps. They do not activate because the voltage drop across the Front Side Marker Lamps is much higher than that across the Turn Lamp Filaments. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Trunk Lamp > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch Trunk Lid With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Trunk Lamp > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch > Page 9806 Rear Luggage Compartment With Pull-Down Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Trunk Lamp > Trunk Lamp Switch > Component Information > Locations > Rear Compartment Lid Latch Switch > Page 9807 Back View Of LH Instrument Panel Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Flasher > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Indicator > Component Information > Locations Convenience Center Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement Turn Signal Lamp: Technical Service Bulletins Lighting - Exterior Lamp Condensation and Replacement INFORMATION Bulletin No.: 01-08-42-001H Date: January 05, 2011 Subject: Exterior Lamp Condensation and Replacement Guidelines Models: 2011 and Prior GM Passenger Cars and Trucks (including Saturn) Supercede: This bulletin is being revised to add the 2011 model year. Please discard Corporate Bulletin Number 01-08-42-001G (Section 08 - Body and Accessories). The following information is being provided to better define the causes of condensation in exterior lamps and includes guidelines for determining the difference between a lamp with a normal atmospheric condition (condensation) and a lamp with a water leak. Some exterior lamps, such as cornering, turn signal, backup, headlamps or tail lamps may exhibit very small droplets of water, a fine mist or white fog (condensation) on the inside of the lamp lens. This may be more noticeable on lamps with "multi-lens" designs and may be normal during certain weather conditions. Condensation occurs when the air inside the lamp assembly, through atmospheric changes, reaches the "dew point". When this takes place, the moisture in the air within the lamp assembly condenses, creating a fine mist or white fog on the inside surface of the lamp lens. Most exterior lamps on General Motors vehicles use a vented design and feature a replaceable bulb assembly. They are designed to remove any accumulated moisture vapor by expelling it through a vent system. The vent system operates at all times, however, it is most effective when the lamps are ON or when the vehicle is in motion. Depending on the size, shape and location of the lamp on the vehicle, and the atmospheric conditions occurring, the amount of time required to clear the lamp may vary from 2 to 6 hours. Completely sealed headlamp assemblies (sealed beams) are still used on a limited number of models being manufactured today. These lamps require the replacement of the complete lamp assembly if a bulb filament burns out. Condensation 2006 TrailBlazer Shown A Fine Mist or White Fog on the Inside Surface of the Lamp Lens Occurring After a Period of High Humidity - May be located primarily in the lens corners (near the vents) and SHOULD NOT cover more than half the lens surface. - The condition should clear of moisture when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a SIMILAR performance. If the above conditions are noted, the customer should be advised that replacement of a lamp assembly may not correct this condition. Water Leak New Style Pickup Shown Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Lamp > Component Information > Technical Service Bulletins > Lighting - Exterior Lamp Condensation and Replacement > Page 9819 Numerous & Various Size Drops of Water Collecting on the Inside Surface of the Lamp Lens After the Vehicle Has Been Exposed to Rain or a Car Washing Environment - A condition that covers more than half the surface of the lamp lens. - An accumulation of water in the bottom of the lamp assembly. - A condition that WON'T clear when the vehicle is parked in a dry environment, or when the vehicle is driven with the lights ON. - A comparison of the equivalent lamp on the opposing side of the vehicle indicates a different performance. Any of the above conditions would indicate the need to service the lens or lamp assembly. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Lamp > Component Information > Locations > LH Turn Signal Lamp: Locations LH LH Rear of Vehicle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Lamp > Component Information > Locations > LH > Page 9822 Turn Signal Lamp: Locations RH RH Rear of Vehicle Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Switch > Component Information > Locations Turn Signal Switch: Locations Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Switch > Component Information > Locations > Page 9826 RH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Switch > Component Information > Locations > Page 9827 C210: Turn Signal Switch Assembly Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Switch > Component Information > Locations > Page 9828 Turn Signal Switch: Service and Repair Fig. 9 Lock Plate Retaining Ring Removal Fig. 10 Turn Signal Electrical Connector & Wiring Isolation Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Turn Signals > Turn Signal Switch > Component Information > Locations > Page 9829 Fig. 11 Turn Signal Switch Removal From Column Bowl Fig. 12 Turn Signal Switch Replacement 1. Disconnect battery cable, then remove steering wheel and column to instrument panel trim cover. 2. On models with telescoping column, remove bumper spacer and snap ring retainer. 3. On models less telescoping column, remove cover from lock plate. 4. On all models, using a suitable tool, compress lock plate (horn contact carrier on tilt models) and remove snap ring (C-ring on tilt models), Fig. 9. 5. Remove lock plate, cancelling cam, upper bearing preload spring, thrust washer and signal lever. 6. Remove turn signal lever or actuating arm screw, if equipped, or on models with column mounted wiper switch, pull lever straight out of detent. Depress hazard warning button, then unscrew button. 7. Pull connector from bracket and wrap upper part of connector with tape to prevent snagging wires during removal, Fig. 10. 8. On Tilt models, position shifter housing in Low position. Remove harness cover. 9. On models less tilt remove retaining screws and remove switch, Fig. 11 AND 12. 10. Reverse procedure to install Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Lighting and Horns > Underhood Lamp > Component Information > Locations Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Heated Glass Element > Heated Glass Element Relay > Component Information > Locations Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Heated Glass Element > Heated Glass Element Relay > Component Information > Locations > Page 9838 LO Blower Relay, Rear Defog Relay And HI Blower Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Heated Glass Element > Heated Glass Element Switch > Component Information > Diagrams Rear Defogger Control Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Rear Defogger > Component Information > Technical Service Bulletins > A/C - Broken Rear Window Defogger Grid Detection Rear Defogger: Technical Service Bulletins A/C - Broken Rear Window Defogger Grid Detection Bulletin No.: 04-08-48-001B Date: June 28, 2005 INFORMATION Subject: Rear Window Defogger - Broken Heating Grid Detection Method Models: 2006 and Prior Passenger Cars and Light Duty Trucks (Including Saturn) 2003-2006 HUMMER H2 2006 HUMMER H3 Supercede: This bulletin is being revised to add the 2006 model year and additional models. Please discard Corporate Bulletin Number 04-08-48-001A (Section 08 - Body and Accessories). The addition of vertical grid lines to the heated back window defogger circuits has made it difficult to detect broken defogger grid lines. In the past, it was a simple matter to use a voltmeter to check the continuity of each grid line in order to locate a non-functional line. Some new design back windows have two vertical grid lines that connect all of the horizontal grid lines together, thereby providing alternate routes for the electrical current to follow. This makes the old test method ineffective. If the vehicle does not have the vertical lines, the old (line-by-line) test methods can be used. Materials Required ^ Permatex(R) Quick Grid, GM P/N 12346001, or equivalent ^ A small ball of fine steel wool Type 00, or ^ Optional - A strip of liquid crystal heat sensitive paper, 51 mm x 305 mm (2 in x 12 in) or similar size (Contact Edmund Scientific at 800-728-6999 for part number CR30723-70 or go to www.scientificsonline.com), or ^ Optional-A portable infrared thermometer, GE-46819, available from Kent-Moore (1-800-345-2233), or equivalent. Correction There are three distinct zones across the back window that must be checked. They are: ^ the driver's side outboard of the two vertical lines ^ the passenger side outboard of the two vertical lines ^ the central zone that falls between the two vertical lines To detect a broken grid line in any of the above three zones and to isolate the exact location of the break, perform the following steps: Caution: ^ Approved safety glasses and gloves should be worn when performing this procedure to reduce the chance of personal injury. ^ Cover the rear shelf area to prevent damage to the interior trim material. 1. Start the engine and turn on the back window defogger. 2. Take the ball of fine steel wool and twist one end to a point. Move the point slowly across each grid line. Be sure to start at the far side of the zone and move it to the opposite side of the zone. When you bridge the grid line break with the steel wool, you will see a small spark. Repeat the test over the same area to be sure you have accurately located the break. Mark the exact location of the grid line break. Repeat this portion of the test for each grid line. If you do not see a spark at any point, it is possible that there are two breaks in the same line and zone. Close visual inspection using a magnifying glass may be the only way to locate breaks in this case. 3. The following are provided as an alternative way to detect a non-functional grid line. If available, use in addition to the steel wool. 3.1. Method using liquid crystal heat sensitive paper: Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Rear Defogger > Component Information > Technical Service Bulletins > A/C - Broken Rear Window Defogger Grid Detection > Page 9846 Important: The first part of the test must be completed quickly before the entire surface of the back window becomes warm. 3.1.1. From outside the vehicle, place the heat sensitive paper (dull surface in contact with the glass) against the top driver side grid line. Start the engine and turn on the back window defogger. A distinct color change will take place at each conductive grid line. Repeat for the bottom grid lines until they have all been checked in the driver side zone. 3.1.2. Repeat the process for the passenger side and center area zones. 3.1.3. If no color change is noted for a grid line, place a crayon or china marker check mark beside it. Mark each grid line in the zone where it is non-conductive and, therefore, not heating up. More than one broken grid line may be found. 3.2. Method using portable infrared thermometer: 3.2.1. Start the engine and turn on the rear back window defogger. 3.2.2. From inside the vehicle, start at the top driver side grid line and slowly run the portable infrared thermometer vertically down the rear window contacting each grid line. You should be able to see a district variation in temperature readings. 3.2.3. Mark each grid line in the zone where it is non-conductive and, therefore, not heating up. More than one broken grid line may be found. 3.2.4. Repeat the process for the passenger side and center area zones. 4. Use Permatex(R) Quick Grid, GM P/N 12346001, or equivalent, to repair each broken grid line. Follow the manufacturer's instructions. 5. Wait 24 hours before turning the defogger on, or the repair can be fast cured using a heat gun, 260°C - 371°C (500°F - 700°F). Hold the heat gun within 25 - 51 mm (1-2 in) from the repair point for 2 to 3 minutes. 6. Recheck the grid line with the heat sensitive paper or portable infrared thermometer to ensure that the line is now functional and that the repair was successful. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Relays and Modules - Windows and Glass > Heated Glass Element Relay > Component Information > Locations Plenum View Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Relays and Modules - Windows and Glass > Heated Glass Element Relay > Component Information > Locations > Page 9851 LO Blower Relay, Rear Defog Relay And HI Blower Relay Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Heated Glass Element Switch > Component Information > Diagrams Rear Defogger Control Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations Power Window Switch: Component Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 9860 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 9861 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 9862 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 9863 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Component Locations > Page 9864 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Sensors and Switches - Windows and Glass > Power Window Switch > Component Information > Locations > Page 9865 Power Window Switch: Diagrams Master Power Window Switch Assembly C1 and C2 Power Window Switch LH And RH Rear RH Front Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Motor > Component Information > Locations > Component Locations Power Window Motor: Component Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Motor > Component Information > Locations > Component Locations > Page 9871 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Motor > Component Information > Locations > Component Locations > Page 9872 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Motor > Component Information > Locations > Component Locations > Page 9873 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Switch > Component Information > Locations > Component Locations Power Window Switch: Component Locations LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Switch > Component Information > Locations > Component Locations > Page 9878 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Switch > Component Information > Locations > Component Locations > Page 9879 RH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Switch > Component Information > Locations > Component Locations > Page 9880 LH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Switch > Component Information > Locations > Component Locations > Page 9881 RH Rear Door And B Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Switch > Component Information > Locations > Component Locations > Page 9882 LH Front Door And A Pillar Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Power Window Switch > Component Information > Locations > Page 9883 Power Window Switch: Diagrams Master Power Window Switch Assembly C1 and C2 Power Window Switch LH And RH Rear RH Front Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Glass > Back Window Glass > Component Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information Back Window Glass: Technical Service Bulletins Body - Vehicle Glass Distortion Information INFORMATION Bulletin No.: 00-08-48-005D Date: September 10, 2010 Subject: Distortion in Outer Surface of Vehicle Glass Models: 2011 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 00-08-48-005C (Section 08 - Body and Accessories). Distortion in the outer surface of the windshield glass, door glass or backlite glass may appear after the vehicle has: - Accumulated some mileage. - Been frequently washed in automatic car washes, particularly "touchless" car washes. This distortion may look like a subtle orange peel pattern, or may look like a drip or sag etched into the surface of the glass. Some car wash solutions contain a buffered solution of hydrofluoric acid which is used to clean the glass. This should not cause a problem if used in the correct concentration. However, if not used correctly, hydrofluoric acid will attack the glass, and over time, will cause visual distortion in the outer surface of the glass which cannot be removed by scraping or polishing. If this condition is suspected, look at the area of the windshield under the wipers or below the belt seal on the side glass. The area of the glass below the wipers or belt seal will not be affected and what looks like a drip or sag may be apparent at the edge of the wiper or belt seal. You may also see a line on the glass where the wiper blade or the belt seal contacts the glass. Important The repair will require replacing the affected glass and is not a result of a defect in material or workmanship. Therefore, is not covered by New Vehicle Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Glass > Front Corner Window Glass > Component Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information Front Corner Window Glass: Technical Service Bulletins Body - Vehicle Glass Distortion Information INFORMATION Bulletin No.: 00-08-48-005D Date: September 10, 2010 Subject: Distortion in Outer Surface of Vehicle Glass Models: 2011 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 00-08-48-005C (Section 08 - Body and Accessories). Distortion in the outer surface of the windshield glass, door glass or backlite glass may appear after the vehicle has: - Accumulated some mileage. - Been frequently washed in automatic car washes, particularly "touchless" car washes. This distortion may look like a subtle orange peel pattern, or may look like a drip or sag etched into the surface of the glass. Some car wash solutions contain a buffered solution of hydrofluoric acid which is used to clean the glass. This should not cause a problem if used in the correct concentration. However, if not used correctly, hydrofluoric acid will attack the glass, and over time, will cause visual distortion in the outer surface of the glass which cannot be removed by scraping or polishing. If this condition is suspected, look at the area of the windshield under the wipers or below the belt seal on the side glass. The area of the glass below the wipers or belt seal will not be affected and what looks like a drip or sag may be apparent at the edge of the wiper or belt seal. You may also see a line on the glass where the wiper blade or the belt seal contacts the glass. Important The repair will require replacing the affected glass and is not a result of a defect in material or workmanship. Therefore, is not covered by New Vehicle Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Glass > Front Door Window Glass > System Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information Front Door Window Glass: Technical Service Bulletins Body - Vehicle Glass Distortion Information INFORMATION Bulletin No.: 00-08-48-005D Date: September 10, 2010 Subject: Distortion in Outer Surface of Vehicle Glass Models: 2011 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 00-08-48-005C (Section 08 - Body and Accessories). Distortion in the outer surface of the windshield glass, door glass or backlite glass may appear after the vehicle has: - Accumulated some mileage. - Been frequently washed in automatic car washes, particularly "touchless" car washes. This distortion may look like a subtle orange peel pattern, or may look like a drip or sag etched into the surface of the glass. Some car wash solutions contain a buffered solution of hydrofluoric acid which is used to clean the glass. This should not cause a problem if used in the correct concentration. However, if not used correctly, hydrofluoric acid will attack the glass, and over time, will cause visual distortion in the outer surface of the glass which cannot be removed by scraping or polishing. If this condition is suspected, look at the area of the windshield under the wipers or below the belt seal on the side glass. The area of the glass below the wipers or belt seal will not be affected and what looks like a drip or sag may be apparent at the edge of the wiper or belt seal. You may also see a line on the glass where the wiper blade or the belt seal contacts the glass. Important The repair will require replacing the affected glass and is not a result of a defect in material or workmanship. Therefore, is not covered by New Vehicle Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Glass > Front Door Window Glass > System Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information > Page 9897 Front Door Window Glass: Technical Service Bulletins Body - Side Window Chipping Information INFORMATION Bulletin No.: 06-08-64-001B Date: October 20, 2009 Subject: Information on Side Door Window Glass Chipping Caused by Hanging Vehicle Key Lock Box Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn) 2010 and Prior HUMMER H2, H3 2009 and Prior Saab 9-7X Supercede: This bulletin is being revised to add vehicles and model years and to include all types of door window glass. Please discard Corporate Bulletin Number 06-08-64-001A (Section 08 - Body & Accessories). - In several warranty parts review cases, side door window glass was observed with a chip or chips on the top side of the window glass. Dealer contacts confirmed that they use a vehicle key lock box on the front side door window glass. - A random selection of side door glass returns will be conducted to confirm adherence. If a side door glass is discovered with a chip or chips in the location previously described, the side door glass will be returned to the dealership for debit. Example of Side Door Glass - DO NOT place a vehicle key lock box on a side door window glass. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Glass > Front Door Window Glass > System Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information > Page 9898 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Glass > Quarter Window Glass > Component Information > Technical Service Bulletins > Body - Vehicle Glass Distortion Information Quarter Window Glass: Technical Service Bulletins Body - Vehicle Glass Distortion Information INFORMATION Bulletin No.: 00-08-48-005D Date: September 10, 2010 Subject: Distortion in Outer Surface of Vehicle Glass Models: 2011 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 00-08-48-005C (Section 08 - Body and Accessories). Distortion in the outer surface of the windshield glass, door glass or backlite glass may appear after the vehicle has: - Accumulated some mileage. - Been frequently washed in automatic car washes, particularly "touchless" car washes. This distortion may look like a subtle orange peel pattern, or may look like a drip or sag etched into the surface of the glass. Some car wash solutions contain a buffered solution of hydrofluoric acid which is used to clean the glass. This should not cause a problem if used in the correct concentration. However, if not used correctly, hydrofluoric acid will attack the glass, and over time, will cause visual distortion in the outer surface of the glass which cannot be removed by scraping or polishing. If this condition is suspected, look at the area of the windshield under the wipers or below the belt seal on the side glass. The area of the glass below the wipers or belt seal will not be affected and what looks like a drip or sag may be apparent at the edge of the wiper or belt seal. You may also see a line on the glass where the wiper blade or the belt seal contacts the glass. Important The repair will require replacing the affected glass and is not a result of a defect in material or workmanship. Therefore, is not covered by New Vehicle Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Handle > Component Information > Technical Service Bulletins > Rear Door Window/Handle - Revised Service Procedure Technical Service Bulletin # 631038 Date: 960801 Rear Door Window/Handle - Revised Service Procedure File In Section: 10 - Body Bulletin No.: 63-10-38 Date: August, 1996 SERVICE MANUAL UPDATE Subject: Revised Service Procedures for Rear Door Window Regulator and Rear Door Outside Handle Models: 1994-96 Chevrolet Caprice, Impala SS This bulletin is being issued to revise information for the rear door window regulator and rear door outside handle service procedures in Section 10-6 of the Service Manual. To service the rear door window regulator, it is necessary to remove the door armrest support, which is not mentioned in the Service Manual. To service the rear door outside handle, it is necessary to remove the door armrest support and the locking system module which is not mentioned in the Service Manual. Listed below are the updated procedures for each component. Important: The following labor times have been updated to reflect the revised procedures: Labor Labor Operation Description Time B4520/21 Rear Door Outside Handle 1.0 hr C0380/81 Rear Door Manual Window 1.3 hrs Regulator C0382/83 Rear Door Power Window 1.3 hrs Regulator Rear Door Window Regulator Remove or Disconnect 1. Rear side door trim. Refer to "Rear Side Door Trim". 2. Rear side door armrest support by drilling out rivets. 3. Rear side door water deflector by peeling away from door. Caution: Tape rear side door window to rear side door frame. If rear side door window drops into rear side door personal injury or rear side door window damage may result. 4. Support rear side door window in the position needed to access regulator-to-window sash rivets, by taping window to door frame using a cloth backed tape. 5. Rear side door locking system module. Refer to "Rear Side Door Locking Module". 6. Rear side door window regulator-to-window sash rivets using a 5/16 inch drill bit. 7. Bolts securing regulator cam to door inner panel. 8. Window regulator electrical connector, if power window regulator. 9. Window regulator-to-door rivets. 10. Window regulator reinforcement, if manual window regulator. 11. Window regulator from door. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Handle > Component Information > Technical Service Bulletins > Rear Door Window/Handle - Revised Service Procedure > Page 9907 ^ The window regulator and motor are serviced as a unit. Install or Connect 1. Window regulator to door. 2. Window regulator reinforcement, if manual window regulator. 3. Window regulator-to-door rivets. 4. Window regulator electrical connector, if power window regulator. 5. Bolts securing window regulator cam to door inner panel. 6. Rear side door window regulator-to-sash rivets. 7. Rear side door locking system module. Refer to "Rear Side Door Locking System Module". 8. Remove tape securing window to door frame. 9. Rear side door water deflector. 10. Armrest support and rivets. 11. Rear side door trim. Refer to "Rear Side Door Trim". Rear Side Door Outside Handle Remove or Disconnect 1. Fully raise window. 2. Rear side door trim. Refer to "Rear Side Door Trim". 3. Armrest support by drilling out rivets. 4. Peel back upper edge of water deflector. 5. Rear side door locking system module rivets and screws. 6. Move rear side door locking system module downward and forward until the outside handle rod is visible through the door lock opening. 7. Disconnect handle rod from handle by inserting a flat bladed tool through the door lock opening and unclipping retainer. 8. Door locking system module from door. 9. Outside handle nuts. 10. Outside handle from door. 11. Outside handle rod from locking system module. Install or Connect 1. Outside handle rod to handle using a new retainer. 2. Hold handle in the open position and install into door. 3. Outside handle nuts. Tighten Tighten outside handle nuts to 5 N.m (44 lb in.). 4. Door locking system module, screws and rivets. Do not connect outside handle rod at this time. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windows > Window Handle > Component Information > Technical Service Bulletins > Rear Door Window/Handle - Revised Service Procedure > Page 9908 Tighten Tighten door locking system module screws to 10 N.m (89 lb in.). Adjust Adjust door outside handle rod by holding rod in the full up position and rotating barrel nut until the barrel nut aligns with the lever on the door lock. 5. Door outside handle rod to locking system module. 6. Water deflector into place. 7. Armrest support and rivets. 8. Rear side door trim. Refer to "Rear Side Door Trim". Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > Customer Interest: > 09-08-48-006 > Sep > 09 > Body - Stain/Film On Windshield Glass Perimeter Windshield: Customer Interest Body - Stain/Film On Windshield Glass Perimeter TECHNICAL Bulletin No.: 09-08-48-006 Date: September 18, 2009 Subject: Clear Stain or Film on Inside Perimeter of Windshield Glass (Clean/Polish Glass) Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn and Saab) 2010 and Prior HUMMER H2, H3 Condition Some customers may comment on a clear stain or film on the inside of the windshield glass. This condition appears along the outer edges of the glass along the top, bottom or A-pillar areas. Normal glass cleaning procedures will not remove the stain. Cause The assembly plant uses a clear sealer/primer on the outer edge of the windshield glass to improve adhesion to the urethane adhesive that bonds the windshield glass to the vehicle body. Excess sealer/primer may drip or flow onto the windshield and cause a stain. Once the sealer/primer dries, it may appear to have etched the glass. Correction Note A "white" type of toothpaste is recommended for this repair. Gel-type toothpaste may provide less satisfactory results. Use a small amount of toothpaste on a soft, cotton cloth to polish the stained area. It may be necessary to wrap the cloth around a paint stir stick or a similar tool to reach the lower corners of the windshield glass. After polishing the glass, clean the inside of the windshield glass with a clean, damp, cotton cloth and verify all of the stain is removed. Do not use any cleaners or solvents - use only clean warm water. Warranty Information (excluding Saab U.S. Models) For vehicles repaired under warranty, use: Warranty Information (Saab U.S. Models) For vehicles repaired under warranty, use the table. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > Customer Interest: > 09-08-48-006 > Sep > 09 > Body - Stain/Film On Windshield Glass Perimeter > Page 9917 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > Customer Interest: > 09-08-48-002A > Mar > 09 > Body - Marks/Stains on Windshield When Wet Windshield: Customer Interest Body - Marks/Stains on Windshield When Wet TECHNICAL Bulletin No.: 09-08-48-002A Date: March 19, 2009 Subject: Marks/Stains on Windshield When Wet (Clean Windshield) Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn and Saab) 2010 and Prior HUMMER H2, H3 Supercede: This bulletin is being revised to update the models and model years. Please discard Corporate Bulletin Number 09-08-48-002 (Section 08 - Body and Accessories). Condition Some owners may comment that marks/stains appear on the windshield when the windshield is wet. Cause This condition may be caused by contact between the windshield and the vacuum hoses or other tools used in the assembly process. This contact may leave a residue that creates a water repellent surface on the glass which, in wet conditions, appear as marks/stains on the surface. Correction Important DO NOT REPLACE THE WINDSHIELD FOR THIS CONDITION. To clean the windshield, use Eastwood Glass Polishing Compound*. Follow the manufacturer's directions for product use. Use only hand tools. DO NOT USE POWER TOOLS. Parts Information Eastwood Glass Polishing Compound 1-800-343-9353 (for overseas inquiries: +1-610-705-2200) http://www.eastwoodco.com/ *We believe this source and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such items which may be available from other sources. Warranty Information For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 06-08-43-003C > Feb > 11 > Glass/Body - Windshield Wiper Performance Windshield: All Technical Service Bulletins Glass/Body - Windshield Wiper Performance INFORMATION Bulletin No.: 06-08-43-003C Date: February 21, 2011 Subject: Windshield Wiper Performance, Cleaning Instructions and Maintenance Models: 2012 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2010 and Prior Isuzu Medium Duty Trucks 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add the 2011 and 2012 model year. Please discard Corporate Bulletin Number 06-08-43-003B (Section 08 - Body and Accessories). Wiper Concerns Most concerns about windshield wiper performance are the result of dirty wiper blades, damaged wiper blades, or worn out blades that are continuing to be used beyond their useful life. Depending on environmental conditions, wiper blades can have dramatic differences in lifespan. Here are some tips and guidelines to maximize wiper performance to avoid damage to the blades, and to avoid unnecessary replacements. Many wiper blades are being replaced under warranty with reviews showing there is nothing wrong with the returned blades other than a build-up of dirt. Additionally, advise the customer to review the information in their Owner Manual. Inspection and Cleaning Scheduled Maintenance - Inspect your wipers rubber blades every 4-6 months or 12,000 km (7,500 mi) for wear, cracking or contamination. - Clean the windshield and the rubber wiper blades (using the procedure below) if the blades are not clearing the glass satisfactorily. If this does not correct the problem, then replace the rubber elements. Cleaning Procedure Important Avoid getting windshield washer fluid on your hands. Wear rubber gloves or avoid direct contact with washer fluid. Important Do not use gasoline, kerosene, or petroleum based products to clean wiper blades. - Clean the rubber blades using a lint free cloth or paper towel soaked with windshield washer fluid or a mild detergent. You should see significant amounts of dirt being removed on the cloth. - Be sure to wash the windshield thoroughly when you clean the blades. Bugs, road grime, sap and a buildup of car wash/wax treatments may additionally cause wiper streaking. Tip For a larger scale buildup on the windshield, use a non-abrasive cleaner such as Bon-Ami* (www.faultless.com) cleanser with a wet sponge, being sure to use plenty of water to avoid scratching the glass. Flush the surface and body panels completely. Tip For day-to-day exterior glass cleaning and to maintain a streak free appearance, suggest Vehicle Care Glass Cleaner, P/N 88862560 (in Canada, 992727). This product is an easy to use foaming cleaner that quickly removes dirt and grime from glass surfaces. Tip Interior glass should be cleaned with plain, clean water to eliminate any film or haze on the window and help prevent fogging, a major customer dissatisfier. Refer to Corporate Bulletin Number 03-00-89-006D for more information. The New Vehicle Pre-Delivery Inspection form also recommends using plain water to clean interior glass. *"We believe this material to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 06-08-43-003C > Feb > 11 > Glass/Body - Windshield Wiper Performance > Page 9927 Avoiding Wiper Damage The following are major contributors to wiper damage. Some of these you can control and others are environmental concerns. - Extremely dusty areas (such as driving on dirt roads) may cause the wipers rubber edge to wear quickly and unevenly. - Sand and salt used on roads for increasing winter traction and ice control will cause the wiper blades to wear quicker. Areas with significant snowfall require more frequent blade replacements. - Heat and time may cause the rubber blades to take a "permanent set" resulting in the rubber not flexing and turning over uniformly. This condition may result in streaking and/or unwiped areas. - Rubber blades are easily cut or torn when using ice scrapers. Likewise pulling blades up off a frozen windshield can tear the rubber. Exercise caution when clearing ice and snow. - Using your wipers to "wear through" frost and ice, instead of allowing the defrosters to melt the ice, can dull, nick or tear the rubber blades. - Banging wipers on the glass to remove ice and snow may cause the blade to bend, dislodging the rubber and causing potential scratching of the windshield. - Ice can form in the pin joints of the wipers, which can cause streaking and unwiped areas. To remove ice from pin joints, compress the blade and rubber edge with your hand to loosen the frozen joints. Consider using Winter Blades that have a rubber cover to avoid this condition. Note GM does not recommend the use of any spray on/wipe on windshield treatments or washer fluid additives. The variation in friction that results on the glass from the use of these products causes wipers to chatter and have premature wear. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 00-08-48-005D > Sep > 10 > Body - Vehicle Glass Distortion Information Windshield: All Technical Service Bulletins Body - Vehicle Glass Distortion Information INFORMATION Bulletin No.: 00-08-48-005D Date: September 10, 2010 Subject: Distortion in Outer Surface of Vehicle Glass Models: 2011 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 00-08-48-005C (Section 08 - Body and Accessories). Distortion in the outer surface of the windshield glass, door glass or backlite glass may appear after the vehicle has: - Accumulated some mileage. - Been frequently washed in automatic car washes, particularly "touchless" car washes. This distortion may look like a subtle orange peel pattern, or may look like a drip or sag etched into the surface of the glass. Some car wash solutions contain a buffered solution of hydrofluoric acid which is used to clean the glass. This should not cause a problem if used in the correct concentration. However, if not used correctly, hydrofluoric acid will attack the glass, and over time, will cause visual distortion in the outer surface of the glass which cannot be removed by scraping or polishing. If this condition is suspected, look at the area of the windshield under the wipers or below the belt seal on the side glass. The area of the glass below the wipers or belt seal will not be affected and what looks like a drip or sag may be apparent at the edge of the wiper or belt seal. You may also see a line on the glass where the wiper blade or the belt seal contacts the glass. Important The repair will require replacing the affected glass and is not a result of a defect in material or workmanship. Therefore, is not covered by New Vehicle Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 09-08-48-006 > Sep > 09 > Body - Stain/Film On Windshield Glass Perimeter Windshield: All Technical Service Bulletins Body - Stain/Film On Windshield Glass Perimeter TECHNICAL Bulletin No.: 09-08-48-006 Date: September 18, 2009 Subject: Clear Stain or Film on Inside Perimeter of Windshield Glass (Clean/Polish Glass) Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn and Saab) 2010 and Prior HUMMER H2, H3 Condition Some customers may comment on a clear stain or film on the inside of the windshield glass. This condition appears along the outer edges of the glass along the top, bottom or A-pillar areas. Normal glass cleaning procedures will not remove the stain. Cause The assembly plant uses a clear sealer/primer on the outer edge of the windshield glass to improve adhesion to the urethane adhesive that bonds the windshield glass to the vehicle body. Excess sealer/primer may drip or flow onto the windshield and cause a stain. Once the sealer/primer dries, it may appear to have etched the glass. Correction Note A "white" type of toothpaste is recommended for this repair. Gel-type toothpaste may provide less satisfactory results. Use a small amount of toothpaste on a soft, cotton cloth to polish the stained area. It may be necessary to wrap the cloth around a paint stir stick or a similar tool to reach the lower corners of the windshield glass. After polishing the glass, clean the inside of the windshield glass with a clean, damp, cotton cloth and verify all of the stain is removed. Do not use any cleaners or solvents - use only clean warm water. Warranty Information (excluding Saab U.S. Models) For vehicles repaired under warranty, use: Warranty Information (Saab U.S. Models) For vehicles repaired under warranty, use the table. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 09-08-48-006 > Sep > 09 > Body - Stain/Film On Windshield Glass Perimeter > Page 9936 Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 09-08-48-002A > Mar > 09 > Body - Marks/Stains on Windshield When Wet Windshield: All Technical Service Bulletins Body - Marks/Stains on Windshield When Wet TECHNICAL Bulletin No.: 09-08-48-002A Date: March 19, 2009 Subject: Marks/Stains on Windshield When Wet (Clean Windshield) Models: 2010 and Prior Passenger Cars and Trucks (Including Saturn and Saab) 2010 and Prior HUMMER H2, H3 Supercede: This bulletin is being revised to update the models and model years. Please discard Corporate Bulletin Number 09-08-48-002 (Section 08 - Body and Accessories). Condition Some owners may comment that marks/stains appear on the windshield when the windshield is wet. Cause This condition may be caused by contact between the windshield and the vacuum hoses or other tools used in the assembly process. This contact may leave a residue that creates a water repellent surface on the glass which, in wet conditions, appear as marks/stains on the surface. Correction Important DO NOT REPLACE THE WINDSHIELD FOR THIS CONDITION. To clean the windshield, use Eastwood Glass Polishing Compound*. Follow the manufacturer's directions for product use. Use only hand tools. DO NOT USE POWER TOOLS. Parts Information Eastwood Glass Polishing Compound 1-800-343-9353 (for overseas inquiries: +1-610-705-2200) http://www.eastwoodco.com/ *We believe this source and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such items which may be available from other sources. Warranty Information For vehicles repaired under warranty, use the table above. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 83-15-16 > Oct > 98 > New Windshield/Glass Urethane Adhesive Caulking Kit Windshield: All Technical Service Bulletins New Windshield/Glass Urethane Adhesive Caulking Kit File In Section: 10 - Body Bulletin No.: 83-15-16 Date: October, 1998 INFORMATION Subject: New Windshield and Stationary Glass Urethane Adhesive Caulking Kit Models: 1990-99 All Passenger Cars and Trucks As a result of a change from standard viscosity urethane to high-viscosity urethane, a new Urethane Adhesive Caulking Kit, P/N 12346392, is now available from GMSPO. This kit contains the "High Viscosity" Urethane Adhesive for thicker and more consistent bead size applications. When applied properly, this new high viscosity urethane in many instances will eliminate the need for depth setting blocks or the damming material to control squeeze out. The following is the contents of the new kit: Like the standard viscosity urethane contained in kit (P/N 12346284) that it replaces, it is a one-part, moisture cure product with curing times that vary as a result of changes in either temperature or humidity. THE REQUIRED TIME FOR THIS NEW ONE-PART MATERIAL to ensure a safe installation of stationary glass before returning the vehicle to the customer, IS A MINIMUM OF SIX (6) HOURS AT 70°F (21°C) AND 30% RELATIVE HUMIDITY. Alternate equivalent materials for this kit may be available from a local glass repair shop under the following product numbers: Other manufacturers of Urethane Adhesive that have documented their ability to meet or exceed General Motors specification # 3651M (Performance Requirements for Stationary Glass Bonding Adhesive System Service) are also considered to be equivalent to GM Kit (P/N 12346392). In previously published Corporate Bulletin Number 73-10-54, increasing customer demands for faster service have resulted in quicker two-part urethane adhesives to be made available. Essex Beta Seal U216* (two-part urethane adhesive) also meets the General Motors 3651M Specification and can be Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 83-15-16 > Oct > 98 > New Windshield/Glass Urethane Adhesive Caulking Kit > Page 9945 used when the customer demands quicker repair of the vehicle than the above described one-part product can provide. This two-part, chemical cure product requires ONE (1) TO ONE-AND-ONE-HALF (1-1/2) HOURS FOR CURING BEFORE RETURNING THE VEHICLE TO THE CUSTOMER. This two-part product also requires primers on the glass and pinchweld surfaces. The primers and applicator daubers are not included with this two-part product and therefore, must be purchased separately. In addition, this two-part product requires a special applicator (gun) for proper mixing and dispensing of the adhesive. Important: The U216 product is NOT available from GMSPO and must be obtained locally. * We believe this source and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such products which may be available from other sources. When using either of the above described products, make sure to follow the manufacturer's directions for application and drying times. For information regarding the removal and installation of stationary glass, consult the appropriate Service Manual. Parts information P/N Description 12346392 Urethane Adhesive Caulking Kit Parts are expected to be available from GMSPO, 10/12/98. Important: The previously recommended adhesive kit (P/N 12346284) will no longer be available from GMSPO once inventory is exhausted. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 72-05-04 > Aug > 97 > Warranty - Guidelines for Claiming Windshield Replace Windshield: All Technical Service Bulletins Warranty - Guidelines for Claiming Windshield Replace File In Section: Warranty Administration Bulletin No.: 72-05-04 Date: August, 1997 WARRANTY ADMINISTRATION Subject: Guidelines for Claiming C0034 - Windshield Replacement Models: 1989-98 Passenger Cars and Light Duty Trucks The purpose of this bulletin is to provide retail and wholesale service personnel with guidelines for using the above subject labor operations. In an effort to understand the windshield replacements, the following two phase approval process is being implemented. We feel this approach will allow GM to be responsive to repair decisions on vehicles over 10,000 miles (16,000KMS), while providing you, our dealers, the empowerment to address customer needs on those cases requiring repairs early in the vehicle's life, under 10,000 miles (16,000KMS). Effective with repair orders dated on or after September 1, 1997, dealers are to be guided by the following: ^ Windshield replacement on vehicles under 10,000 miles (16,0OOKMS) can only be made after Service Management inspection, review and approval. This approval must be noted on the repair order clearly identifying the defect and reason for replacement. This comment must be submitted in the comment field of the claim for engineering review. ^ Windshield replacement on vehicles over 10,000 miles (16,000KMS) can only be made after Service Management inspection, review and approval from the divisional service representative. Vehicles may be required to be held for wholesale inspection. This approval must be noted on the repair order clearly identifying the defect and reason for replacement. This comment must be submitted in the comment field of the claim for engineering review. The claim will require wholesale authorization for payment. Additional Requirements ^ Windshields replaced must be held for the normal parts retention period and the defect should be clearly identified on the glass by means of tape and/or a grease pencil. ^ Sublet windshield replacements, like other sublet repairs are to be claimed for actual dealership cost less any discounts and or allowances offered. Sublet repairs cannot exceed the normal allowance provided to the dealership had the repair been completed in-house. See your GM Policy and Procedure Manual for the complete guidelines. Windshields damaged by normal wear, road hazards, vandalism, or other physical damage are not eligible for warranty coverage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Technical Service Bulletins for Windshield: > 73-10-54 > May > 97 > Windshield - Two-Part Urethane Adhesive For Installation Windshield: All Technical Service Bulletins Windshield - Two-Part Urethane Adhesive For Installation File In Section: 10 - Body Bulletin No.: 73-10-54 Date: May, 1997 INFORMATION Subject: Two-Part Urethane Adhesive For Windshield Installations Models: 1997 And Prior Passenger Cars and Trucks (Using Urethane Adhesive To Retain Windshields) General Motors passenger cars and trucks use urethane adhesive as a means to retain the windshield in the body opening. The urethane adhesive is used to bond the windshield in the opening, increasing vehicle structure. The current recommended urethane adhesive, GM P/N 12346284, is a one-part moisture cure product that requires a minimum curing period of 6 hours at room temperature before returning the vehicle to the customer. Increasing customer demands for faster service in recent years have resulted in quicker cure two-part urethane adhesives. Essex Beta Seal U216* (two-part urethane adhesive) meets the General Motors 3651M Specification (Performance Requirements for Stationary Glass Bonding Adhesive System Service) and can be used when the customer demands quicker repair of the vehicle than the current one-part materials can provide. Either of these products can be used when glass replacement is performed. The differences between these products are as follows: The CURRENT URETHANE ADHESIVE KIT, GM P/N 12346284, IS A ONE-PART ADHESIVE. It includes the necessary glass and pinchweld primers and is specified in Service Manuals for General Motors' vehicles. Since this is a "moisture cure" product, the curing time for this one-part material will vary with changes to either temperature or humidity. The REQUIRED TIME FOR THIS ONE-PART MATERIAL to ensure a safe installation of stationary glass before returning the vehicle to the customer IS A MINIMUM OF SIX (6) HOURS AT 70°F (21°C) AND 30% RELATIVE HUMIDITY. ESSEX BETA SEAL U216 IS A TWO-PART ADHESIVE MATERIAL THAT PROVIDES FOR A ONE (1) TO ONE AND ONE HALF (11/2) HOUR CURE BEFORE RETURNING THE VEHICLE TO THE CUSTOMER. This product also requires primers on the glass and pinchweld surfaces. This product requires a special applicator for the mixing and dispensing of the adhesive. When using this (or any) product, make sure to follow the manufacturer's directions for application and drying times. Parts Information Parts are currently available from GMSPO. * We believe this source and their product to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such products which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Other Service Bulletins for Windshield: > 06-08-43-003C > Feb > 11 > Glass/Body - Windshield Wiper Performance Windshield: All Technical Service Bulletins Glass/Body - Windshield Wiper Performance INFORMATION Bulletin No.: 06-08-43-003C Date: February 21, 2011 Subject: Windshield Wiper Performance, Cleaning Instructions and Maintenance Models: 2012 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2010 and Prior Isuzu Medium Duty Trucks 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add the 2011 and 2012 model year. Please discard Corporate Bulletin Number 06-08-43-003B (Section 08 - Body and Accessories). Wiper Concerns Most concerns about windshield wiper performance are the result of dirty wiper blades, damaged wiper blades, or worn out blades that are continuing to be used beyond their useful life. Depending on environmental conditions, wiper blades can have dramatic differences in lifespan. Here are some tips and guidelines to maximize wiper performance to avoid damage to the blades, and to avoid unnecessary replacements. Many wiper blades are being replaced under warranty with reviews showing there is nothing wrong with the returned blades other than a build-up of dirt. Additionally, advise the customer to review the information in their Owner Manual. Inspection and Cleaning Scheduled Maintenance - Inspect your wipers rubber blades every 4-6 months or 12,000 km (7,500 mi) for wear, cracking or contamination. - Clean the windshield and the rubber wiper blades (using the procedure below) if the blades are not clearing the glass satisfactorily. If this does not correct the problem, then replace the rubber elements. Cleaning Procedure Important Avoid getting windshield washer fluid on your hands. Wear rubber gloves or avoid direct contact with washer fluid. Important Do not use gasoline, kerosene, or petroleum based products to clean wiper blades. - Clean the rubber blades using a lint free cloth or paper towel soaked with windshield washer fluid or a mild detergent. You should see significant amounts of dirt being removed on the cloth. - Be sure to wash the windshield thoroughly when you clean the blades. Bugs, road grime, sap and a buildup of car wash/wax treatments may additionally cause wiper streaking. Tip For a larger scale buildup on the windshield, use a non-abrasive cleaner such as Bon-Ami* (www.faultless.com) cleanser with a wet sponge, being sure to use plenty of water to avoid scratching the glass. Flush the surface and body panels completely. Tip For day-to-day exterior glass cleaning and to maintain a streak free appearance, suggest Vehicle Care Glass Cleaner, P/N 88862560 (in Canada, 992727). This product is an easy to use foaming cleaner that quickly removes dirt and grime from glass surfaces. Tip Interior glass should be cleaned with plain, clean water to eliminate any film or haze on the window and help prevent fogging, a major customer dissatisfier. Refer to Corporate Bulletin Number 03-00-89-006D for more information. The New Vehicle Pre-Delivery Inspection form also recommends using plain water to clean interior glass. *"We believe this material to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Other Service Bulletins for Windshield: > 06-08-43-003C > Feb > 11 > Glass/Body - Windshield Wiper Performance > Page 9959 Avoiding Wiper Damage The following are major contributors to wiper damage. Some of these you can control and others are environmental concerns. - Extremely dusty areas (such as driving on dirt roads) may cause the wipers rubber edge to wear quickly and unevenly. - Sand and salt used on roads for increasing winter traction and ice control will cause the wiper blades to wear quicker. Areas with significant snowfall require more frequent blade replacements. - Heat and time may cause the rubber blades to take a "permanent set" resulting in the rubber not flexing and turning over uniformly. This condition may result in streaking and/or unwiped areas. - Rubber blades are easily cut or torn when using ice scrapers. Likewise pulling blades up off a frozen windshield can tear the rubber. Exercise caution when clearing ice and snow. - Using your wipers to "wear through" frost and ice, instead of allowing the defrosters to melt the ice, can dull, nick or tear the rubber blades. - Banging wipers on the glass to remove ice and snow may cause the blade to bend, dislodging the rubber and causing potential scratching of the windshield. - Ice can form in the pin joints of the wipers, which can cause streaking and unwiped areas. To remove ice from pin joints, compress the blade and rubber edge with your hand to loosen the frozen joints. Consider using Winter Blades that have a rubber cover to avoid this condition. Note GM does not recommend the use of any spray on/wipe on windshield treatments or washer fluid additives. The variation in friction that results on the glass from the use of these products causes wipers to chatter and have premature wear. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Other Service Bulletins for Windshield: > 00-08-48-005D > Sep > 10 > Body - Vehicle Glass Distortion Information Windshield: All Technical Service Bulletins Body - Vehicle Glass Distortion Information INFORMATION Bulletin No.: 00-08-48-005D Date: September 10, 2010 Subject: Distortion in Outer Surface of Vehicle Glass Models: 2011 and Prior GM Passenger Cars and Trucks 2009 and Prior HUMMER H2 2010 and Prior HUMMER H3 2005-2009 Saab 9-7X 2010 and Prior Saturn Supercede: This bulletin is being revised to add model years. Please discard Corporate Bulletin Number 00-08-48-005C (Section 08 - Body and Accessories). Distortion in the outer surface of the windshield glass, door glass or backlite glass may appear after the vehicle has: - Accumulated some mileage. - Been frequently washed in automatic car washes, particularly "touchless" car washes. This distortion may look like a subtle orange peel pattern, or may look like a drip or sag etched into the surface of the glass. Some car wash solutions contain a buffered solution of hydrofluoric acid which is used to clean the glass. This should not cause a problem if used in the correct concentration. However, if not used correctly, hydrofluoric acid will attack the glass, and over time, will cause visual distortion in the outer surface of the glass which cannot be removed by scraping or polishing. If this condition is suspected, look at the area of the windshield under the wipers or below the belt seal on the side glass. The area of the glass below the wipers or belt seal will not be affected and what looks like a drip or sag may be apparent at the edge of the wiper or belt seal. You may also see a line on the glass where the wiper blade or the belt seal contacts the glass. Important The repair will require replacing the affected glass and is not a result of a defect in material or workmanship. Therefore, is not covered by New Vehicle Warranty. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Other Service Bulletins for Windshield: > 83-15-16 > Oct > 98 > New Windshield/Glass Urethane Adhesive Caulking Kit Windshield: All Technical Service Bulletins New Windshield/Glass Urethane Adhesive Caulking Kit File In Section: 10 - Body Bulletin No.: 83-15-16 Date: October, 1998 INFORMATION Subject: New Windshield and Stationary Glass Urethane Adhesive Caulking Kit Models: 1990-99 All Passenger Cars and Trucks As a result of a change from standard viscosity urethane to high-viscosity urethane, a new Urethane Adhesive Caulking Kit, P/N 12346392, is now available from GMSPO. This kit contains the "High Viscosity" Urethane Adhesive for thicker and more consistent bead size applications. When applied properly, this new high viscosity urethane in many instances will eliminate the need for depth setting blocks or the damming material to control squeeze out. The following is the contents of the new kit: Like the standard viscosity urethane contained in kit (P/N 12346284) that it replaces, it is a one-part, moisture cure product with curing times that vary as a result of changes in either temperature or humidity. THE REQUIRED TIME FOR THIS NEW ONE-PART MATERIAL to ensure a safe installation of stationary glass before returning the vehicle to the customer, IS A MINIMUM OF SIX (6) HOURS AT 70°F (21°C) AND 30% RELATIVE HUMIDITY. Alternate equivalent materials for this kit may be available from a local glass repair shop under the following product numbers: Other manufacturers of Urethane Adhesive that have documented their ability to meet or exceed General Motors specification # 3651M (Performance Requirements for Stationary Glass Bonding Adhesive System Service) are also considered to be equivalent to GM Kit (P/N 12346392). In previously published Corporate Bulletin Number 73-10-54, increasing customer demands for faster service have resulted in quicker two-part urethane adhesives to be made available. Essex Beta Seal U216* (two-part urethane adhesive) also meets the General Motors 3651M Specification and can be Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Other Service Bulletins for Windshield: > 83-15-16 > Oct > 98 > New Windshield/Glass Urethane Adhesive Caulking Kit > Page 9968 used when the customer demands quicker repair of the vehicle than the above described one-part product can provide. This two-part, chemical cure product requires ONE (1) TO ONE-AND-ONE-HALF (1-1/2) HOURS FOR CURING BEFORE RETURNING THE VEHICLE TO THE CUSTOMER. This two-part product also requires primers on the glass and pinchweld surfaces. The primers and applicator daubers are not included with this two-part product and therefore, must be purchased separately. In addition, this two-part product requires a special applicator (gun) for proper mixing and dispensing of the adhesive. Important: The U216 product is NOT available from GMSPO and must be obtained locally. * We believe this source and their products to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such products which may be available from other sources. When using either of the above described products, make sure to follow the manufacturer's directions for application and drying times. For information regarding the removal and installation of stationary glass, consult the appropriate Service Manual. Parts information P/N Description 12346392 Urethane Adhesive Caulking Kit Parts are expected to be available from GMSPO, 10/12/98. Important: The previously recommended adhesive kit (P/N 12346284) will no longer be available from GMSPO once inventory is exhausted. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Other Service Bulletins for Windshield: > 72-05-04 > Aug > 97 > Warranty - Guidelines for Claiming Windshield Replace Windshield: All Technical Service Bulletins Warranty - Guidelines for Claiming Windshield Replace File In Section: Warranty Administration Bulletin No.: 72-05-04 Date: August, 1997 WARRANTY ADMINISTRATION Subject: Guidelines for Claiming C0034 - Windshield Replacement Models: 1989-98 Passenger Cars and Light Duty Trucks The purpose of this bulletin is to provide retail and wholesale service personnel with guidelines for using the above subject labor operations. In an effort to understand the windshield replacements, the following two phase approval process is being implemented. We feel this approach will allow GM to be responsive to repair decisions on vehicles over 10,000 miles (16,000KMS), while providing you, our dealers, the empowerment to address customer needs on those cases requiring repairs early in the vehicle's life, under 10,000 miles (16,000KMS). Effective with repair orders dated on or after September 1, 1997, dealers are to be guided by the following: ^ Windshield replacement on vehicles under 10,000 miles (16,0OOKMS) can only be made after Service Management inspection, review and approval. This approval must be noted on the repair order clearly identifying the defect and reason for replacement. This comment must be submitted in the comment field of the claim for engineering review. ^ Windshield replacement on vehicles over 10,000 miles (16,000KMS) can only be made after Service Management inspection, review and approval from the divisional service representative. Vehicles may be required to be held for wholesale inspection. This approval must be noted on the repair order clearly identifying the defect and reason for replacement. This comment must be submitted in the comment field of the claim for engineering review. The claim will require wholesale authorization for payment. Additional Requirements ^ Windshields replaced must be held for the normal parts retention period and the defect should be clearly identified on the glass by means of tape and/or a grease pencil. ^ Sublet windshield replacements, like other sublet repairs are to be claimed for actual dealership cost less any discounts and or allowances offered. Sublet repairs cannot exceed the normal allowance provided to the dealership had the repair been completed in-house. See your GM Policy and Procedure Manual for the complete guidelines. Windshields damaged by normal wear, road hazards, vandalism, or other physical damage are not eligible for warranty coverage. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Windows and Glass > Windshield > Component Information > Technical Service Bulletins > All Other Service Bulletins for Windshield: > 73-10-54 > May > 97 > Windshield - Two-Part Urethane Adhesive For Installation Windshield: All Technical Service Bulletins Windshield - Two-Part Urethane Adhesive For Installation File In Section: 10 - Body Bulletin No.: 73-10-54 Date: May, 1997 INFORMATION Subject: Two-Part Urethane Adhesive For Windshield Installations Models: 1997 And Prior Passenger Cars and Trucks (Using Urethane Adhesive To Retain Windshields) General Motors passenger cars and trucks use urethane adhesive as a means to retain the windshield in the body opening. The urethane adhesive is used to bond the windshield in the opening, increasing vehicle structure. The current recommended urethane adhesive, GM P/N 12346284, is a one-part moisture cure product that requires a minimum curing period of 6 hours at room temperature before returning the vehicle to the customer. Increasing customer demands for faster service in recent years have resulted in quicker cure two-part urethane adhesives. Essex Beta Seal U216* (two-part urethane adhesive) meets the General Motors 3651M Specification (Performance Requirements for Stationary Glass Bonding Adhesive System Service) and can be used when the customer demands quicker repair of the vehicle than the current one-part materials can provide. Either of these products can be used when glass replacement is performed. The differences between these products are as follows: The CURRENT URETHANE ADHESIVE KIT, GM P/N 12346284, IS A ONE-PART ADHESIVE. It includes the necessary glass and pinchweld primers and is specified in Service Manuals for General Motors' vehicles. Since this is a "moisture cure" product, the curing time for this one-part material will vary with changes to either temperature or humidity. The REQUIRED TIME FOR THIS ONE-PART MATERIAL to ensure a safe installation of stationary glass before returning the vehicle to the customer IS A MINIMUM OF SIX (6) HOURS AT 70°F (21°C) AND 30% RELATIVE HUMIDITY. ESSEX BETA SEAL U216 IS A TWO-PART ADHESIVE MATERIAL THAT PROVIDES FOR A ONE (1) TO ONE AND ONE HALF (11/2) HOUR CURE BEFORE RETURNING THE VEHICLE TO THE CUSTOMER. This product also requires primers on the glass and pinchweld surfaces. This product requires a special applicator for the mixing and dispensing of the adhesive. When using this (or any) product, make sure to follow the manufacturer's directions for application and drying times. Parts Information Parts are currently available from GMSPO. * We believe this source and their product to be reliable. There may be additional manufacturers of such products. General Motors does not endorse, indicate any preference for or assume any responsibility for the products from this firm or for any such products which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Washer Fluid Level Switch > Component Information > Locations LH Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations Windshield Washer Switch: Component Locations Upper LH Side Of Steering Column LH I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations > Page 9986 Windshield Washer Switch: Connector Locations Lower LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations > Page 9987 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Page 9988 C216: Windshield Wiper/Washer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations Wiper Switch: Component Locations Upper LH Side Of Steering Column LH I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations > Page 9993 Wiper Switch: Connector Locations Lower LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations > Page 9994 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 9995 C216: Windshield Wiper/Washer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 9996 Wiper Switch: Service and Repair Fig. 18 Windshield Wiper Switch. Standard Steering Column Fig. 19 Windshield Wiper Switch. Tilt Steering Column Fig. 20 Windshield Wiper Switch Actuator Pivot Pin Replacement 1. Disconnect battery ground cable and remove turn signal switch as outlined under Turn Signal Switch, Service and Repair. See: Lighting and Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Sensors and Switches - Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 9997 Horns/Sensors and Switches - Lighting and Horns/Turn Signal Switch/Service and Repair 2. Remove ignition lock, ignition switch and dimmer switch as outlined under Ignition Lock, Ignition Switch and Dimmer Switch Service and Repair. See: Steering and Suspension/Steering/Steering Column/Service and Repair 3. Remove ignition lock housing retaining screws and housing, Fig.18 and 19.. 4. Remove pivot bolt and wiper switch from lock housing, Fig. 20. 5. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Washer Fluid Level Indicator > Component Information > Description and Operation Washer Fluid Level Indicator: Description and Operation The windshield washer solvent tank has a switch that closes when the washer solvent level becomes low, illuminating the Low Washer Fluid indicator. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Washer Fluid Level Indicator > Component Information > Testing and Inspection > Low Solvent Indicator on, Solvent Level OK Washer Fluid Level Indicator: Testing and Inspection Low Solvent Indicator "on", Solvent Level OK Fig. 95 Chart 4: Low Washer Fluid Indicator On At All Times Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Washer Fluid Level Indicator > Component Information > Testing and Inspection > Low Solvent Indicator on, Solvent Level OK > Page 10003 Washer Fluid Level Indicator: Testing and Inspection Low Solvent Indicator Inoperative Fig. 94 Chart 3: Low Washer Fluid Indicator Inoperative Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Washer Fluid Level Switch > Component Information > Locations LH Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Motor > Component Information > Locations LH Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Motor > Component Information > Testing and Inspection > Washer Will Not Operate Windshield Washer Motor: Testing and Inspection Washer Will Not Operate Fig. 73 Test 8: Washer Will Not Operate. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Motor > Component Information > Testing and Inspection > Washer Will Not Operate > Page 10012 Windshield Washer Motor: Testing and Inspection Washer Will Not Shut Off Fig. 74 Test 9: Washer Will Not Shut Off. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Pump > Component Information > Locations > Wiper Washer Pump Motor, Front Brake Pressure Modulator Valve (With Electronic Brake Control Module) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Pump > Component Information > Locations > Wiper Washer Pump Motor, Front > Page 10017 LH Front Of Engine Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Reservoir > Component Information > Locations Windshield Washer Reservoir: Locations LH Front Of Engine Brake Pressure Modulator Valve (With Electronic Brake Control Module) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations Windshield Washer Switch: Component Locations Upper LH Side Of Steering Column LH I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations > Page 10025 Windshield Washer Switch: Connector Locations Lower LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Component Locations > Page 10026 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Windshield Washer Switch > Component Information > Locations > Page 10027 C216: Windshield Wiper/Washer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Blade > Component Information > Technical Service Bulletins > Glass/Body - Windshield Wiper Performance Wiper Blade: Technical Service Bulletins Glass/Body - Windshield Wiper Performance INFORMATION Bulletin No.: 06-08-43-003C Date: February 21, 2011 Subject: Windshield Wiper Performance, Cleaning Instructions and Maintenance Models: 2012 and Prior GM Passenger Cars and Trucks (including Saturn) 2010 and Prior HUMMER H2, H3 2010 and Prior Isuzu Medium Duty Trucks 2005-2009 Saab 9-7X Supercede: This bulletin is being revised to add the 2011 and 2012 model year. Please discard Corporate Bulletin Number 06-08-43-003B (Section 08 - Body and Accessories). Wiper Concerns Most concerns about windshield wiper performance are the result of dirty wiper blades, damaged wiper blades, or worn out blades that are continuing to be used beyond their useful life. Depending on environmental conditions, wiper blades can have dramatic differences in lifespan. Here are some tips and guidelines to maximize wiper performance to avoid damage to the blades, and to avoid unnecessary replacements. Many wiper blades are being replaced under warranty with reviews showing there is nothing wrong with the returned blades other than a build-up of dirt. Additionally, advise the customer to review the information in their Owner Manual. Inspection and Cleaning Scheduled Maintenance - Inspect your wipers rubber blades every 4-6 months or 12,000 km (7,500 mi) for wear, cracking or contamination. - Clean the windshield and the rubber wiper blades (using the procedure below) if the blades are not clearing the glass satisfactorily. If this does not correct the problem, then replace the rubber elements. Cleaning Procedure Important Avoid getting windshield washer fluid on your hands. Wear rubber gloves or avoid direct contact with washer fluid. Important Do not use gasoline, kerosene, or petroleum based products to clean wiper blades. - Clean the rubber blades using a lint free cloth or paper towel soaked with windshield washer fluid or a mild detergent. You should see significant amounts of dirt being removed on the cloth. - Be sure to wash the windshield thoroughly when you clean the blades. Bugs, road grime, sap and a buildup of car wash/wax treatments may additionally cause wiper streaking. Tip For a larger scale buildup on the windshield, use a non-abrasive cleaner such as Bon-Ami* (www.faultless.com) cleanser with a wet sponge, being sure to use plenty of water to avoid scratching the glass. Flush the surface and body panels completely. Tip For day-to-day exterior glass cleaning and to maintain a streak free appearance, suggest Vehicle Care Glass Cleaner, P/N 88862560 (in Canada, 992727). This product is an easy to use foaming cleaner that quickly removes dirt and grime from glass surfaces. Tip Interior glass should be cleaned with plain, clean water to eliminate any film or haze on the window and help prevent fogging, a major customer dissatisfier. Refer to Corporate Bulletin Number 03-00-89-006D for more information. The New Vehicle Pre-Delivery Inspection form also recommends using plain water to clean interior glass. *"We believe this material to be reliable. There may be additional manufacturers of such material. General Motors does not endorse, indicate any preference for or assume any responsibility for the products or equipment from these firms or any such items which may be available from other sources. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Blade > Component Information > Technical Service Bulletins > Glass/Body - Windshield Wiper Performance > Page 10032 Avoiding Wiper Damage The following are major contributors to wiper damage. Some of these you can control and others are environmental concerns. - Extremely dusty areas (such as driving on dirt roads) may cause the wipers rubber edge to wear quickly and unevenly. - Sand and salt used on roads for increasing winter traction and ice control will cause the wiper blades to wear quicker. Areas with significant snowfall require more frequent blade replacements. - Heat and time may cause the rubber blades to take a "permanent set" resulting in the rubber not flexing and turning over uniformly. This condition may result in streaking and/or unwiped areas. - Rubber blades are easily cut or torn when using ice scrapers. Likewise pulling blades up off a frozen windshield can tear the rubber. Exercise caution when clearing ice and snow. - Using your wipers to "wear through" frost and ice, instead of allowing the defrosters to melt the ice, can dull, nick or tear the rubber blades. - Banging wipers on the glass to remove ice and snow may cause the blade to bend, dislodging the rubber and causing potential scratching of the windshield. - Ice can form in the pin joints of the wipers, which can cause streaking and unwiped areas. To remove ice from pin joints, compress the blade and rubber edge with your hand to loosen the frozen joints. Consider using Winter Blades that have a rubber cover to avoid this condition. Note GM does not recommend the use of any spray on/wipe on windshield treatments or washer fluid additives. The variation in friction that results on the glass from the use of these products causes wipers to chatter and have premature wear. Disclaimer Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Gear Box > Component Information > Service and Repair Wiper Gear Box: Service and Repair 1. Disconnect battery ground cable. 2. Remove right and lefthand wiper arm and hose. 3. Remove lefthand cowl vent screen, then righthand screen. 4. Disconnect plastic nozzle hose from rubber washer hose. 5. Remove wiper linkage access hole cover attaching screws, then remove cover. 6. Disconnect drive link from motor crank arm. 7. Remove linkage to body attaching screws, then remove linkage through access hole. 8. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Motor > Component Information > Locations Engine Harness/U/Hood Electrical Center, Right Side Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Motor > Component Information > Locations > Page 10039 Windshield Wiper Motor Assembly (C1) Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Motor > Component Information > Locations > Page 10040 Wiper Motor: Service and Repair 1. Disconnect battery ground cable. 2. Remove righthand wiper arm and hose. 3. Remove lefthand cowl vent screen, then righthand screen. 4. Remove wiper linkage access hole cover attaching screws, then remove hole cover. 5. Disconnect wiper motor drive link from motor crank arm. 6. Disconnect wiper motor electrical connectors. 7. Remove motor attaching bolts, then remove motor guiding crank arm through access hole. 8. Reverse procedure to install. Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations Wiper Switch: Component Locations Upper LH Side Of Steering Column LH I/P Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations > Page 10045 Wiper Switch: Connector Locations Lower LH Side Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Component Locations > Page 10046 Base Of Steering Column Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 10047 C216: Windshield Wiper/Washer Switch Chevrolet Impala Ss Workshop Manual (V8-350 5.7L VIN P MFI (1995)) Chevrolet Workshop Manuals > Wiper and Washer Systems > Wiper Switch > Component Information > Locations > Page 10048 Wiper Switch: Service and Repair Fig. 18 Windshield Wiper Switch. Standard Steering Column Fig. 19 Windshield Wiper Switch. Tilt Steering Column Fig. 20 Windshield Wiper Switch Actuator Pivot Pin Replacement 1. Disconnect battery ground cable and remove turn signal switch as outlined under Turn Signal Switch, Service and Repair. See: Lighting and